I'll second that. (You could also have headed that "Known Cheaters", but that'll do.)
With that, I'd like to post my own additions:
People that suck:
Green Hill/Hero Chaos Chao/Mr Buu/Mr Poo/Mark Blackwell
prcorby
sonic1001
zac-a-maniac
formarfan
segamaster (hey, he might not be a cheater, but that doesn't stop him from sucking)
sonicmaster03 (need I say more? :o)
People that don't suck:
Rolken
SM
Cybrax
F-Man
SS101
NintenDan
RPGnutter
SprintGod
CosmicFalcon
and any other Power Users I missed (is that it?)
Characters that suck:
All of Team Rose
G-emerl (or whatever he's called, cheap imitation of Metal Sonic <_<)
Characters that don't suck:
Sonic, Tails, Knuckles
Dr. Robotnik (not this Eggman crap >_>)
Team Chaotix
Metal Sonic