For comparison's sake, here's our experience with my wife's X3. It only has about 1,500 miles on it so the fuel consumption will probably continue to improve, but we've been thrilled with its performance to date.

We have the 2.5 X3 with Steptronic Auto (a no-cost option in Canada). Currently, with 100% city driving, it is getting 21.5 miles/U.S. gallon (or about 11L/100 KM). It's a sweet little ride and already three or four of my neighbors are beginning to think about getting one, which is interesting considering the X5 is the SUV of choice in my neighborhood (there must be 30-40 of them within a few block radius of me). I'm looking forward to seeing what the X-Drive will do when the snow flies and I'm on my way to the mountains to ski