Although it is just a game, it gives a better sense of the driving experience than anything else. Every last detail, in terms of driving accuracy, is perfect. The graphics arent the best, but when just driving a car in the game, you don't care.
If what you want is an arcade racing game, with lots of terrible street circuits, then get pgr3 or 4 (not 2, its rubbish), but if you want to race around real circuits with minute accuracy,and in some of the best cars around, get forza 2. Forza 1 was brill, this excells it by a mile.
One complaint is that they could have added more mercedes (SL55, SLK55 etc) but they just tuck with what was in the old game.