I picked up Forza yesterday (already had GT4 before)

I must say the overall driving experience with forza is better TWO-FOLD than GT4. Although the cars do no look at as good, the experience, and environmental graphics are much better. If they could get the car models and reflections on the cars to look like the GT4 models it would get a 10/10! After playing this I dont think I can go back to GT4 at all.

Also On Line play is amazing. No lag experienced, and very good competitors.