It's a racing game with bad gameplay. Probably the worst Sonic out there. Want a racing game? Get F-Zero or Mario Kart, because this game sucks in gameplay. The cutscenes are boring, the history is terrible, and that's pretty much of it. Sucks.
Sonic Riders doesn't boast too many tracks, nor does it have an online mode, which is a shame, but a bit of unique futuristic racing with familiar faces is what I'm after these days, and Sonic Riders delivers on that front hands down.