I bought one of these private sale last year. What a great ride!. I had never driven a vehicle that tight before. Lots of power and handles like a monorail. Rear-wheel-drive with traction control was fantastic in the snow; I was really surprised. Unfortunately the one I bought was a little beat. Rust on the bottom of the doors, front end parts kept loosening up ($400 each), needed pads and rotors, and tires, leaked oil, seemed to be burning coolant, window controls shot, antenna broken, sun-roof broken - you name it, it was broken. But it was a fun car to drive. So I traded it in towards a newer 528i.
Handling and feel of the car.
Better fuel economy! But I think BMW has made this improvement on subsequent models.