Yesterday I drove a 128i convertible from Albuquerque, NM to El Paso, TX - moving the BMW "Komen Drive for the Cure" Cars to their next stop. I found the car to be very impressive and the computer said 30 MPG for the 267 mile drive at about 75 mph or so.
The Chassis/Suspension (quiet and stiff) seemed to me to be an improvement over my 2005 E46 coupe on about the same order as the improvement from E36 to E46. I did notice the shorter wheelbase on a couple of rough/uneven patches where the car felt a little more unsettled than my E46 might. The car cornering was very flat and I noticed that the Goodyear runflats were noticeably less harsh and noisy than I have experienced during drives of the new 3 series cars. This is the first car with runflats that I felt was acceptable in terms of ride quality and noise level. The sport seats felt a little narrower than the sport seats in my e46, but, no complaints.
All in all, I think this car is a winner - now, I just have to get over the runflat/no spare issue.

2005 325I Coupe
2004 530I