What we really like is the fully modeled interiors of the vehicles with functional gauges. The detail is so high, and the vehicle's gauges can be used in place of the HUD.
One of the cool things we saw was the capability to get an instant replay from any point in the game without exiting the race.
We also liked the dynamic racing line that adjusted its braking and acceleration points based on the current speed of the vehicle.
Developers Slightly Mad Studios insist that, while NFS: Shift is more realistic than previous games in the franchise, it is not a hard-core sim like the Gran Turismo or Forza series. Their aim was to make the game more approachable to the casual gamer.
I think there will be room on my shelf for all three games when Need for Speed: Shift hits PS3, Xbox 360, and PC in Fall '09.