Not for casual Gamers!
Bad: Two words: Sucky Soundtrack
Forza Motorsport is easily the best racing simulator on the xbox, (If it's not the only one, I haven't checked) and it packs enough cool features and cars to make any car enthusiast wet his/her pants.
The tracks are varied and diverse, and custom car painting is incredibly fun (and challenging). The game is incredibly difficult though, and casual gamers will NOT like this game.
Other than that, this game is great. The graphics are amazing, yet the damage modeling leaves something to be desired. Rival cars are aggresive and smart, always trying to find a way to beat you.
They did leave out the Lamboughini, but I'll forgive them for that.
The car sounds are good, but the soundtrack is repulsive. Luckily, the game supports Custom Soundtracks.