Ok, but not the best ever.
Graphics-7 The graphics are good, but not the best. The places you race in look good, and feel scale to the cars. The cars look ok, but they are almost boring to look at. But there are a lot of them.
Sound-6 The sound is easily the worst part of the game. The music in the menus isn't good. When race there doesn't seem to be music(and I'm sure there is any). Cars sound fine, even if they pretty much sound the same.
Value-8 This is the best part of the game. There are 750 cars to collect and getting them will take a long time. Multiplayer is great too, and is lots of fun.
Verdict- You should get this game for your kids, or at least rent it for them if they like racing games. And you should rent it if think racing little cars around seems fun to you.