To be fair, my system experience is failrly limited. I've run AD&D (1st & 2nd ed), d20, and GURPS in the last few years. Long long ago I ran WoD, Rifts, and the old d6 Star Wars game. I've never really run a super hero game before, but it seemed like a good setting for a one shot game. If it goes belly up, I'll look into running Champions next time.
How is BESM? The anime game I'm planning on running (Probably VTT) is going to be powerful characters with GEARs. I don't know how well the systems mesh, but I remember my girl friend mentioning the system when I mentioned I was running an anime game.