All reviews I have seen thus far call it the racing game of this generation.
I had the same misgivings regards the physics of the game, but tinkering around with the assist options to get a more realistic feel changed the game entirely.
It's the only game I have played where you can get near simulation levels of feel and also an arcade style feel for a less demanding experience.
I will definatley be getting it for the update in cars and upgrade in graphics. Will post my feelings on the game once I have a few hours hands on experience.
Also, my xbox live connection appears to be dead
Will have a look later and update....