I had a 3.0 as a loaner when my 4.4 was getting prepped for delivery. The 3.0 was functional, but I was surprised, as other posters to this thread were that the 3.0 netted roughly the same mileage. That said I am really pleased with my 4.4 and I'd choose it again in a heartbeat. The ability to accelerate like a giant sports car never ceases to put a grin on my face.

__________________
2013 X5 xDrive3.5i Premium
2002 530I Sport Package
2001 X5 4.4i
2001 M3