I drove it twice for about 20 miles each time. On freeways as well as in the mountains.

Here are my impressions as compared to my 05 4.4

Handling: 4.8 is a lot more composed than my 4.4
Acceleration: This may sound weird, but I did not feel an ounce of difference in acceleration. In fact, dare I say?... it lagged a bit, and the transmission felt rougher. My X5 feels faster especially from 40 to 80 mph.
Interior: Awesome, a lot nicer than my current X. Third row seat??..once again a joke
Exterior: The new X just looks bad a**, especially with the 20's

I love the looks of the new X, however, I need something with a bigger third row. Still leaning towards the piggie Escalade. Maybe BMW will come out with something bigger soon.