Played it for a while, my thoughts:
- The thing looks amazing. The car models aren't as nice as the GT4 models, but the whole game looks 'cleaner'.
- The driving was alright, pretty good actually for a series (hopefully) so early in it's life. GT4 feels better, but that's understandable because they've been at it for a while.
- Didn't have time to go in and tune a car and what not, so I can't comment on the depth of that.
- AI is brilliant, this is one of the majour things GT4 is lacking.
- Damage doesn't add much to the gameplay.
- The Driveatar system isn't as nice as B-spec mode.
Overall, good game, not as good as GT4. That being said, I can't wait for the sequel in the XBOX 360, should be a beast.