I will make this short. The graphics are well done, with all those stages effects, this wins the 8/10.
The sound isn't that great, but is still OK, I'm giving it a 6/10.
The gameplay is well done, with the Turbo, the tornadoes and characters types that lets them grind, fly or punch enemies makes races fun. They're lots of unlockables on the game, and all the boards called "Gears" differs ones from others (not like in zero gravity). This game contains a story mode, that is not the best but it is entertaining. A thing you may take time to masterise are the curves and drifts. I will add this to my Sonic good games, Sonic Riders is the same between GC or PS2, it's all about your preferance. It is not the Sonic race game I expected, Sonic should run on foot instead of going on a floating board, don't he?
Withouts furthers, I put this game an 8.5/10. I hope you enjoyed my review.