In General: Attack is arguably the strongest primary type in the format, however it takes a lot more skill to use than the other two types. Success relies on a good launch and even moreso a strong launch – Attack types can handle most of the defense types I've tried if launched hard enough. Lastly, RF condition is a big deal, too worn and you won't move fast enough, too new and you'll fly out of the stadium. They do stay prime for a good amount of time but if you are really struggling with a CS defender you may want to look at getting a new one or wearing yours in a little.

Metal Wheels:

Gravity: Gravity is arguably the most threatening wheel in the format that has been thoroughly tested (hence why it'll be watched very carefully as the game develops), thanks to its weight, power (particularly with the Attack version of Perseus), and dual spin. However, these properties serve to keep a range of other things in check, particularly stronger defensive threats and Anti-Attack – while the combination of plastic buffers, good weight and often more extreme (in either direction) designs makes Zero G wheels serious defensive threats, their relatively poor balance means if they use RF they will usually fail to outspin Gravity (and Gravity's dual spin also helps negate any advantage given by the availability of Dark Knight). Gravity's shape also makes it effective against a wide range of heights on R145 and TH170 (though leone r145 is certainly no slouch), and thus helps prevent any one defensive track being too dominant. These factors mean that absolute defensive walls are not safe choices, which means things that less effective (but often more interesting) attack wheels stand a chance against should be the most common defense types.
That said, gravity is not that much stronger than the other wheels I'd call competitive (see my post in the Competitive Combos list discussion when I make it if I haven't already), even given the fact I have always found it to work very well for me (and hence may be overrating its effectiveness), and I don't think a ban on it is healthy for the format so long as people do branch out and use the alternatives.

Note about SonoKong Gravity: Just a reminder that SonoKong Gravity wheels should be avoided as they are generally significantly lighter and much less aggressive (but not really any better for spin stealing either). Their L/R's are also more fragile so there really is no reason to buy them.

Pegasis: CRAZY HORSE. If you're heading to a tournament and a Beyblade flies past your ear despite the fact there aren't any stadiums in sight, you can bet Pegasis was involved. Pegasis is explosive. It has aggression on top, and even more on the bottom, and plenty side on as well. It could, however, do with a little more weight behind it as it suffers from pretty heavy recoil, but it is still very much competitive.

Leone: My favourite Attack wheel, and similar in weight and style to Gravity, Leone is definitely one of the strongest Attack wheels in the format (as well as perhaps the second most aggressive after Pegasis) – top three of the things I tried for sure. It has a tonne of smash side-on thanks to its large contact points which have a lot of weight behind them, as well as hanging low over then track AND having an extremely violent top-side, making it dangerous in every direction. Excellent synergy with R145 only makes this better. It's survival could be better, but that's compared to gravity, and it is certainly by no means horrible in that respect.

Screw: This might surprise some people, but I always said if it weren't for the ridiculous defense parts introduced around the same time by the Maximum series (especially BD145, which blocked , Screw would have been hailed as a great Attack Wheel. Guess what? In Limited, where those parts are not present, Screw is a great Attack Wheel. So There.
Screw's quirk is that most of its attack comes from its slopes, and so for best performance they should stay unobstructed, my favourite CW's for it being Pisces, Horogium, and much to the delight of my inner primary school student, Uranus. You'll want to make sure you're hitting your opponent from just below their Metal Wheel if possible, I find that R145 is again a good choice, allowing solid contact with taller opponents and the track helping with lower ones, though if your local meta tends towards taller tracks, TH170 is an excellent choice too. If your metagame is more 145 and down, go low, though I recall preferring 90 to 85 on it back in the day so you may want to compare the two yourself. In exchange for this, however, Screw is one of the most exciting wheels, if it lands a hit just right, it is capable of launches so spectacular even Pegasis would drool over it.
It's worth pointing out that it is hurt significantly less by its need to hit just under the metal wheel than old favourite Vulcan, perhaps due to a greater range of contact points, and also benefits from good synergy with R145, which I'll cover in a little. What I'm trying to say is (if you're of similar or older vintage than me brace yourself) Screw is better than Vulcan.

Lightning:Lightning is consistent, efficient, and left spinicient (rhyming is hard), I didn't use lightning that much because I prefer gravity and find lightning rather dull by comparison, perhaps because it only gets one clear wheel. It's definitely one of the best Attack wheels, though it shines brightest on low tracks, being perhaps the most reliable answer to Low Track Defense setups Attack can muster. Like the other wheels I've covered so far, it also works very well on R145, though it's lack of any real aggression on its underside means R145 does have to do more work than it would otherwise need to. Lightning is great, wonderful and I'm sure it'll have a great time but I probably won't use it myself because I prefer other things.

Ray: I know I said that Ray being on the CC list given it was released alongside CS and RSF was a mistake but in retrospect I was wrong – RS is the specific point at which Ray starts to fail. With it banned, Ray is an excellent Attack MW, again benefitting from amazing synergy with R145, which should be reinforced with a three sided CW like Kerbecs, Unicorno II or Unicorno – the Leones being less worthwhile as they do nothing for Ray's relative flatness (and thus little to help its range). While its ability to attack in any direction other than sideways is somewhat limited, Ray feels somewhat easier to use than the other attack wheels, and is still a very effective wheel overall.
Note there are multiple molds of Ray and one I have is much thinner than the rest, though I have more than one each of Takara and SonoKong Rays, so I cannot be sure where it came from.

Vulcan: Once considered the most powerful Attack wheel in existence, Vulcan returns to the ring to find a metagame somewhat different and less kind than it remembers. Vulcan has a bit of a problem with height, it can deliver some of the hardest hits of anything of its vintage but it really needs to be hitting just under the metal wheel, at least in my experience, and it doesn't seem to work too well on taller tracks. It also doesn't have good synergy with R145, and GB145 and H145 just aren't quite as good. However, underestimate Vulcan at your peril, it's heavy, fast (thanks to all that weight being behind its contact points), and it hits like a truck. It's also very thankful not to have to contend with RS, and as a result I'd still consider it competitive, just make sure you launch real hard to capitalise on its potential for speed.

Quetzalcoatl: Also once considered the most powerful Attack wheel in existence (despite the presence of Lightning and Leone - see Mc Frown's thread titled something along the lines of don't let your empty wallet fool you, I think it's in the advanced forum), Quetz is the least aggressive wheel I'd still call competitive. Its quirk is that it has an element of Force Smash to it. Its contact points aren't the most well exposed, though they're still effective, but of all the non-three-sided wheels, it perhaps is the most effective at compensating for its poor synergy with R145, its sloped undersides being able to deal hard hits to lower opponents – just make sure you've got the weight to back it up.


Things I don't have that could be strong:
Wyvang/Phoenic/Bahamdia and maybe some other ZG Stuff: The hyper aggressive design of many Chrome wheels and their ability to be used in either spin direction, and the fact their poor survival and balance is not particularly detrimental for Attack means they pose a significant threat here.

Metal Fury – Pretty much anything even remotely aggressive: The sheer size of these things makes them major threats and added to this is the more extreme designs resulting from post-maximum series power creep. Or they could end up being horrible recoil laden trash, though from what we've seen this is probably not likely.

In addition to this, Shogun Steel was apparently only released in North America (and Metal Fury was similarly limited – Australia apparently received neither), and therefore if they are too dominant, they will reward part access disproportionately to skill/combo building, so personally I'd like to treat them a little more strictly.

Tracks:
[b]R145: R145 is THE track for Attack. The best wheels are all Three Sided and I strongly believe that has to do with R145. R145 is likely the heaviest track in the format unless something from Zero G is heavier, and it actually has passable offensive ability (without the recoil of H145). It's at a good height for most wheels as well. Basically, you're going to want to have this part.

160-180 heights: This seems like a solid height range for Attack tracks in this format – sharp banking can still let them hit low opponents while they're tall enough to hit 230-height opponents from below reliably. This is based primarily on TH170 (SA165 is slightly better but is too good defensively), which is a very effective track for Attack, at least on wheels with some overhang. Gravity strikes me as the best user I tried, particularly because it is capable of outspinning many low track RF (and with less certaintly RSF) Defense combos when set to taller heights, combinations which are otherwise difficult for Attack to handle reliably while maintaining the ability to hit tall opponents. 160 will probably be a solid choice thanks to its height.

Others: SW145, UW145 are also decent but outclassed by R145, and there's H145 but I really dislike it and don't have much success with it. CH120 is good but the fact it doesn't stay in 145 height well, which it really needs to in a metagame with tall tracks (and the fact the R145 is generally good for multi-height-range attack) means it has lost some of its shine. Low Tracks are extremely good against heights up to 145, but are unable to do anything of note to tall tracks, making them risky but potentially rewarding.
W145 should probably do very well in general, too.

[u]Tips:
RF, R2F, LRF: Choose your favourite (mine is RF) and make sure it's prime. That's really all there is to it. MF, WF, XF and some of the ZG era tips might work out but the results are probably going to end up in Balance rather than here.

Overall
No Big Plastic Disks? No RS, RDF or RB? No obscene weight advantage? Only one or two near-perfect circles? What does defense do in this metagame?
Well for starters it stops making the game boring by dominating attack to the point no one wants to use Attack at tournaments while also being easy to just launch and leave. Secondly, however, it still works quite well, but now has a similar amount of risk to Stamina, and still usually less than Attack. It may take some getting used to if you have never played anything from before the Maximum Series or are just so used to post maximum series MFB you don't know what it's like for Defense to not dominate, but give it a chance.
If you're a defense enthusiast, and have somehow not stopped reading to write an angry response chastising me for my pro attack bias (fun fact: my favourite combo type from any generation are Defensive Zombies from plastics) look at it this way – in this format, you need to put a lot more effort into defense, both in choosing a combination and in using that combination. What I'm saying is, you'll have a much bigger opportunity to prove your love for the type by showing that you can use it better than, shall we say "casual defense users" who just put a defense combination together from the competitive combos list and expect to laugh at attack as long as they don't miss the stadium with their launch. I personally find Defense a lot more fun to use in this generation, and I think you can too.


Wheels

Libra: OH NO IT'S LIBRA RUN FOR YOUR LIVES! Or you know, outspin it, or hit its underside or one of its many bumps and knock it out. See, Libra, despite being the heaviest wheel in the format, has some problems. The biggest is its underside – it both overhangs the track by a fair amount and suffers from quite a lot of recoil. Libra cannot use tall tracks or it will get knocked out by Attack. In addition to this, while it is definitely one of the best Anti-Attack wheels, it still isn't quite as aggressive as it needs to be on RF to truly dent things, and it also isn't quite heavy enough to do what it wants without a heavy enough track. Don't get me wrong, it's very powerful, especially on low tracks, and it will be under very close supervision particularly in terms of balance setups, but Libra is not the be all and end all for defense by any means.

Earth: Earth is plain but also plain good. It has extremely low recoil, decent weight, and solid survival to boot, meaning it is excellent in general and also quite safe to use low tracks with RF, as it deals well with spin stealing attempts. Personally, I find it slightly more reliable than Libra thanks to the low recoil, and it is certainly by no means outclassed by libra defensively.

Reviser ____: Reviser is round and heavy, but suffers from poor balance even in Crystal Up mode, to the point it can't really use RF without getting outspun by attack types. It's still very effective at surviving KO's, however.

Flame: Borderline, but Flame's design means it is slightly harder to connect with on tall tracks. It's no good on anything not in the 220-230 range (preferably 230), and RF may be a bad idea because of increased tilting due to its grip and movement, but on those tracks it is somewhat irksome for Attack types to handle reliably.

Other things: Virgo works okay if it's not being hit at an angle, basically, but this is kinda rare. Dark is passable but not great, as is Grand.
Metal Fury Duo, though I do not own it, may outclass Earth and generally speaking is one of the things I am most concerned about that is still legal.


Tracks:
GB145: The best track for defense at the traditional defense height, GB145 has good weight without the recoil of R145. It is prone to sitting unevenly on Metal System wheels, especially if the facebolt hole of the track cracks (very common from screwing faces too tight), so you should be careful to check for this when testing and competing. It's solid and perhaps the best track for benchmarking. It is also a good height for anti-attack if you want to KO things, though for pure defense 85 is probably better.

85/90: LTDC were about to step into the spotlight when the original BIG PLASTIC DISKâ„¢, BD145, appeared and completely outclassed them, providing even better protection for the underside as well as a massive weight boost and a plastic buffer and generally being a broken piece of carp. However, now the big plastic disks are gone, LTDC finally have their chance to impress and they most certainly do. 85RF and RSF are very difficult for any attacker not also on 85 to handle, whereas CS provides decent survival and solid defense.

TH170/230 etc: Tall Track defense did shut down Low Track Attack, and continues to do so, however they struggle with 145-180 or thereabouts height attackers (basalt was unique in being broken enough to smack them, meaning attack had to resort to BD145 for the extra weight to handle it, and the BD145 meta resulted). However, MF (and to a lesser extent due to the lack of heavy enough wheels WF) and even RF combined with low-recoil, reasonably heavy wheels can be used to make momentum-based combinations focussed on cramping attackers or straight up smashing through them for KO's, though these definitely prefer opposite spin matchups. Generally speaking 230 and the like are still strong but the presence of R145 and tracks between 145 and 230 will make things tougher for them.

Tips:

CS: Solid Defense and Decent Stamina, CS was by far the most popular defense tip before the power creep of 4D produced a wheel called Flash which was basically two sledgehammers tied together. In a less ridiculous metagame, CS returns to its place as an excellent defense tip, however it does sorely miss its big plastic disks, and as such it represents a tradeoff of certainty against attack for more certainty against other defenders and balance types (as well as Anti-Attack, as an Anti-Attack wheel that reliably beats CS defense is almost certainly ban worthy). Also in case you forgot, CS is kinda a hassle with the whole tip condition thing so get ready for more of that.

RSF: RSF is solid, the most similar thing to regular MFB's defense tips, not particularly good stamina but solid enough defense to weather all but the fiercest of attacks. It's not good enough to nullify height matchups but MF-H Earth ___ 85RSF is one of the most solid, dependable defenders I've used. It's good, and with it's brother RS out of the picture RSF finally gets a chance to shine.

MF: An unusual entry and perhaps not on the most stable ground, MF has decent stamina and most importantly for defense, a very good ability to catch the tornado ridge. Its aggression can be good or bad depending on what you're doing, as you can use it to cramp attackers flower patterns and maybe nudge stamina types out of the arena. It shines most in the momentum-based combos mentioned in the 230 section above, but overall is a solid tip as long as you have decent weight on it (so generally it's not great for Low Tracks).

RF: Another one that will upset traditionalists (though probably not as much as people saying "no defense can't move even if that actually lets them take hits better" upset me when I read that argument for the first time), RF has the most grip of any tip in the format and while the extra energy its movement adds to collisions tempers this, it is still very solid, especially with weight and/or low recoil, and it also presents a chance of KOing stamina types that would OS more passive defense tips. 230 is probably something it should shy away from, leaving that to MF (though it can still work at high altitudes in the right setup), and its stamina is very poor, but on low tracks and GB145, as well as in Anti-Attack customs, RF is very hard for attack to deal with, and a key part of defense and is a tip defense lovers will likely need to get used to if they want to succeed with their favourite type.

Stamina is stamina, there's few surprises to be had here and I am not a huge fan of MFB stamina so I'm afraid this might be even more dull than the other sections.
Stamina is hurt by the fact defense no longer completely shuts down attack with little effort because now if you use a stamina combo there's probably actually a chance you'll face attack because people shouldn't be scared to use that. The most interesting thing will be seeing how Spin Stealing, which only took off after the maximum series but doesn't really need parts that are banned from this format (perhaps bar SA165), works as a strategy, though Earth will pose a bit of a problem for them as it is generally quite good at resisting spin steal.
Stamina v Stamina used to rely primarily on height matchups, making for a game within a game, basically, and hopefully that will return.

There's little to say here. Earth, Burn, and Virgo, as well as maybe some metal fury wheels are the ones to go for.
Earth has super low recoil and as such is very reliable.
Burn has better pure stamina but is much more prone to being KO'd due to recoil.
Virgo is somewhere between the two and the shorter spinning copies (the cause of which is completely unknown despite ample investigation) are probably somewhat outclassed, though they still work decently while the "5 Minute Molds" that no one seemed to have any more by the time I'd heard about them would probably be one of the better choices.
Libra also works but doesn't have stamina to hold up to these and as such is better off using 85/90 with D or EWD (SD probably works, EDS might), which leans towards balance in that it can take a hit from weaker attack types and anti-attack while still outspinning defense.
Thermal may be worth trying as some people had success with it, but I was one of the people who didn't.

Parts I don't have:
F230 is probably the track to watch out for here (though perhaps it's more balance like) and it's perhaps the thing being most closely watched in this format as we start having tournaments in it, especially with the publicity it has received in regular MFB and Zero G.

W145 should also be watched closely in case it disrupts the height matchups of old, though whether this warrants a ban will be hotly debated I'm sure.

Metal Wheel wise, Metal Fury Duo and Phantom, and to a lesser extent Scythe, will need to be watched closely. For spin stealing, Dark Knight may be the biggest concern, as IIRC Hasbro's LDD was not so great (which makes sense – rubber that can touch the stadium is generally bad for stamina), but gravity's dual spin may be exploitable (though if this happens it will more likely be due to a particular track/tip than gravity itself).

Okay so I predominantly stuck with the primary types in my testing, only testing variations on them that came close to balance that I was familiar with. This is because there is such a ridiculous range of parts that it'd be impossible for one person to test them all. The lack of BD145 and various wheels limits a lot of staple balance type setups in general but various things still work – MLD CH120XF is perfectly fine as long as you can launch it well (which is very hard to do), for example.