I love this car. I have two young children which means that I need a car with 4 doors. I have owned a '98 E36 M3 sedan - which was fun and a '02 E39 M5 - which was fantastic (apart from the oil leaks & quirky electronic failures) both of which made me an avid M fan. However, when it came time to replace the M5 there was no 4 door M series available. So, I switched to Audi's S4. I was very surprised at how good the Audi was but it did not give me the same driving enjoyment as a BMW. When it came time to change the Audi I looked at the M5 and the M3 sedan. I liked the M5 but I could not see what I was getting for the extra $30K. The M3 is a perfect solution for me and my family... we love it!
Brakes, engine (and exhaust noise at 4-5,000rpm), iDrive, comfort access, iPod integration, M button (so much easier than the two fingered salute on the E39 M5), phone integration, comfortable ride in normal mode and acceleration!
Nothing critical but it does need a larger gas tank, addition of European style rear fog lights for use in heavy rain, back up camera, Acura style voice commands for navigation, headlamp washers