I recently bought my M3 and haven't had a chance to spend too much time with it but the time I have spent in it has been quite impressive. The handling is one of the most notable characteristics. It hugs the road with every turn. The engine is great... smooth, quiet, and delivers when you put the foot to the pedal. Low end torque is great.
Classic styling, looks, and the fact that it's a BMW says it all
Interior can use a little work. Vader seats aren't supportive enough.