Knuckles' Chaotix is fantastic. It wouldn't catch half the flack it does if it hadn't been for the fact that it's neither a traditional Sonic game nor a new 3D Sonic game, like people were hoping for. The bungee function really does work, and once you get used to it, the game is FAST.
That's right, Knuckles Chaotix is the fastest Sonic game.
It does have a couple of flaws, though. The random stage select, as well as the random partner select, really shouldn't have existed (though you can get around them with bonus stage items). Also, they did an awful lot of idea recycling in each Zone. It's almost impossible to tell them all apart.
Still, the first level and the greenhouse level are some of the best in Sonic history, I think, especially with their awesome music. Too bad my 32X is in America, or I'd give it a spin right now.