Was going to post this actually..
I hired it friday.. I am in two minds, but it is pretty damn good. Reminds me of a cross in some ways between NFSU and Gran Turismo (of course). Graphics aren't quite as crisp, or the lighting or something as realistic as Gran Turismo in my mind - feels a bit cartoony.
Replays aren't as good either. Its great though you can actually detail up your car with brand name kits and bits, and the mods seem a little more "real" . Its a bit of a straight ripoff at times though, but hey, no gt series for xbox means they have to try something.
It has all the good cars, but in a way, it doesn't counter so much to the enthusiast who just wants to drive a little daihatsu Move or something obscure and see what you can do with it. So you end up with the better cars, but this makes it a bit boring in some ways...
Lets not even discuss the music..
Smashes can effect the driveability of your car and i was fighting to stay steering straight after rear ending in one race the other night, it depends on what difficulty you have set it to for this setting "mild, medium, hard". I like the fact that ramming and shunting cars to win will lead you off the track, whereas it can get you wins that you shouldn't in GT.
I like the fact that you can get more win $ by using harder difficulty, turning off traction control, running manual, etc. This is the way it should be, to make the game a good challenge, and make you want to learn the full complexities of driving without any driving aids.
I like the fact that as you mod your car it goes up a different class, although this makes the game a heck of a lot harder.
Its scary in that many of the tracks like Tsubuka, nuremberg are exactly the same, so it almost feels like you're playing a slighty different Gran Turismo at times, just on xbox.