Lulz, I've beaten good players with Sonic, Boxob. He's a lot of work, but it's doable. Still, fighting GaW, Snake, ROB, or (if one exists) a good MK is a nightmare, and something that you encounter quite frequently. Falco does well against most of these characters, and as such, will prolly become my secondary.
Umbeh, Wolf has beaten a lot of good Colorado players their first time playing against him. The fact that he can crank out a million moves a second and have it be incredibly hard to punish (the first couple times you play him) is what was causing a problem. My original response was to outspam him with Zelda, but I can beat 'em with Sonic nao. Dair is too amazing.