I test drove the Q7 4.2 and found the interior to be very nice, the blindspots atrocious and the ride to be way too "bouncy". The handling was really mushy. I wanted to like it but came away disappointed.
I drove the X5 4.8 after it and loved it. It was everything the Q7 was not. The only downside I found was the small trunk/lack of third row seating - though they are offering a jump seat in the trunk in the 2010s.