Sonic R isn't too bad though it has it's flaws. I'll state the good & bad about it.
The Good
-Fair amount of characters to choose
-Well designed level backgrounds. Infact, that's probally one of my favourite things about this game
-Balloon Battle is a laugh with friends
-Music is very good especially in the old days
-Most characters are well balanced for a game like this. I mean, Metal Knuckles can near enough keep up, and pretty much outdo Super Sonic
The Flaws & Bad stuff
-Braking is some of the worst I've come across
-Certain weather conditions can make races extremely cheap especially the snow condition
-Spin Dash is useless as well as Eggman's missile which pretty much does jack.
-Turning can be a real pain sometimes, which sharp turn maneuvure comes in handy for this
-Single player is extremely short, and there are lack of levels. Even the extras afterwards still make it short. If there was about 15 - 20 levels, then it'd be much better