Well i got this yesterday (after trading in GT5 and a couple of other games)
Imho this is wayyyyy better than GT5. Even down to simple things like if you buy and upgrade you can sell the upgrade and get your money back. If you sell a fully modified car you get the base price you paid for the car and all the money for the upgrades back etc.
The driving physics seem to be a hell of a lot better than GT5 as well. Cornering is more realistic for example if you lift off mid bend you can induce lift off oversteer. Also when you get to tuning the car each option is explained briefly but in enough detail so that you understand how this will affect what the car does. Damage is realistic i rolled a car when shunted in a race and it totally destroyed the car as it would do. No reset to track and carry on (although you can have that option if you just select visual only damage)
What i also like is the level of detail on the cars. All the cars are fully rendered not just a select view.
All in all the first impressions after playing for a couple of hours i'm mightily impressed