I just bought teh xbox and forza motorsports when it came out about a month ago and have been playing it everyday in love with the online play, but had to sell it because of a speeding ticket I got. Now, I went back and played gran turismo, and gran turismo is a way better simulator then Forza. The only things forza had better then gt4 would have to be the way the scenery was 3d, and tires marks as well as body kits exhaust and damage, and of course online play. But gran turismo 4's Frames per second is so much better, everything is so much smoother. I mean, after not playing ps2 for a whole month and playing only forza and jumping back into gt4 I think gt4 is the greater of the two games. Forza has a way better layout, because of how it classes the cars, but it gets really arcade like in the fact that only certain cars are the best in certain classes, and noone can keep up with those cars regardless of the driving. Also turbo Enzo's get on my nerves, these are a few of the things that ruin the real factor for me. Also the gripping physic's in gran turismo 4 feel better, it feels alot more realistic when you are driving courses such as nurburgring in gt4. I don't feel that Forza is as much of a simulator as gt4 is, gt4 feels alot more realistic in grip driving, the only sucky part of gt4 is the drifting, it feels very unrealistic. Overall, I just feel that the only thing's gt4 is lacking is tire marks, damage, mountain courses, visible mod's, realistic AI, online play, better car classes, and to go back to gt3 physic's as far as drifting is concerned. But if we are comparing pure motorsports feel of the cars and tracks, gt4 wins over forza, forza is to much of an arcade racer, thats why its so much fun, gt4 is more of a raw simulator of real life driving.