I just went over 200 miles on the odometer this morning. Had the X1 (sDrive28i) since last Friday. Live and work in Los Angeles area, so I guess that constitutes "city" driving. Still on the first tank, obviously (actually not even at half a tank, if I recall correctly). Computer MPG read-out is now 24.7. The LA freeways do open up, believe it or not, from time to time, and that's when I can see the numbers creep up as I watch the read-out. In bad freeway traffic, if I use Eco-Pro, I can see the MPG hold steady. It is in street traffic with frequent full stops for lights and stop signs that the MPG dips.
So I am pretty happy with the X1 MPG at this very early stage.