Oil up an LL2 or Zero G Compact Launcher that doesn't skip (it's basically a 50/50 chance with takara ones, seems to be due to the chassis rather than the components from what I tried today), and you can get the same max speed as a beylauncher. Just been playing around with this myself today/recently as I keep breaking beylaunchers and really like the ZGCL's design, basically just launching gravity perseus with that and my beylauncher L's and yeah, it requires more strength (launch power is all about speed, more resistance = more speed) but yeah, they seem to be dead equal. The kick takes a bit of getting used to, and that's what puts people off I think, but if you get a good one and oil it up a little so it doesn't grind away at itself and has lower friction, you'll get there.
Just finished oiling up 5 LL2's (well, I oiled seven before realizing the last two had been from my "no this skips" pile) for lending at the tournament I'm planning (obviously with some advice on using them because that kick is a bit of a shock at first), and I'm planning on competing with a ZGCL and a left string launcher (I like the feel of them in left for some reason).
Kai-V: Disagree on compact launchers not being decent, they're really nicely designed (mostly through the addition of what seems to be lower friction plastic at certain points - ripcord entry and also atop the shaft, where a lot of wear can happen otherwise), just a matter of getting lucky and finding one that doesn't skip out of the box, then oiling it up so it doesn't grind itself to the point it starts skipping (which happens
extremely fast if you launch synchromes with them - I found this out the hard way, sadly, and as it seems to be the chassis responsible for skipping or not (the LL2 design seems sturdier than the plastics one but I haven't used any non-lubricated one much) so any wear to that and you're done). They're internally the same as an LL2 power-wise (i.e. the same gear is used) but they have a few improvements (though honestly, a good LL2 is a very serviceable launcher anyway, they do actually seem to have kept in mind that they were building a launcher for heavier beys - it's just there's only so much you can do with plastic). If there is a power difference between what can be got out of an oiled-up ZGCL and a Beylauncher, it's small enough to not be evident without perhaps some intensive solo spins.
For what it's worth, I would rather use string launchers for synchromes because the kick becomes more problematic for them, but I find they break more easily or at least are harder to replace and extra weight only worsens that, would probably not recommend a ZGCL for Synchromes for kids.