I have mixed feelings on this game. Clearly the best way to get my point across is to compare it to forza. One thing to be careful about directly comparing them is that you must only look at the R4, R3, R2, and R1 cars in forza.
The Good:
1. AI - Wow, this is a massive difference from Forza. Not only are you racing 15 other cars, but they are smart for once. I could not stand the AI in forza, in this I love it! The AI will actively leave the racing line to block or pass. The AI will go way out of the way to avoid any collisions also. I can see the AI cars lock up from time to time and that also adds to why they are awesome.
2. Cars - Sure a lot of people will say there are not enough cars.... bullroar. For me the best cars in Forza 2 were the race classes, and I could give a dam less for the others. I have not made it into the really fast stuff yet, but I am loving the cars.
3. Driving - If you feel like playing with driving aids dont bother with this game. Turning any of the aids on really ruins what this game has over forza. Playing with all the aids off is a real treat and rewards you for being light on the pedals.
4. Qualifying - Dear god thank you!!!!! No longer will be punish faster drivers by putting them to the back of the grid. On the other hand I love setting myself in last place when playing the AI since they are such a treat to pass and race against.
5. Sense of Speed - Forza never felt that fast to me. Sure in R1 it was fast, but this feels a lot quicker. Grid does show speed the best though.
Bad
1. Graphics - Sure I don't measure how good a driving game by how good it looks. This is why I bought this over Grid. I wont lie though, its really hard to not be dissapointed of how un impressive this game looks, esp when next to grid or PGR4.
2. Sound - there are some excellent sounds to be found, but like someone said they all seem compressed or something. I love the tranny wind and the backfires, but this game has nothing on other games.
3. Sense of weight - I dont know, I just think forza gave you a better feeling of weight and momentum.