Throw the Vmax out. Valken has issues, and there's a good chance you'll get one that won't shoot 10 bps, much less keep up with tourney rates.
Too is basically just the Halo B2 in a sturdier shell with the prophecy anti-jam.
Scion is basically the Prophecy Z2 in a new HaloB shell.
Scion will perform slightly better, but is slightly more expensive. Toolless battery door, IMO, is worth it though. I've considered picking one up to replace my Too because most of the shell is now jb weld because it's cracking so badly.