That pretty much matches my observations here:
http://forums.carmudgeons.com/showthread.php?t=35023
1. Car looks good in and out.
2. Is very large to drive, doesn't feel "natural" or "small" around you, a good bit of bmw-ness lost, especially due to the steering, the e-class had as good (if not better) steering.
3. n55 feels worse than the n54, especially in a larger car, but I really think it's the engine's character.
4. 550i power is awesome, gadgets too if you're into that sort of thing. But the version with the awesome power is even more out of touch.