My M3 Coupe is the finest car I have ever driven. The Porsche guys will say I never drove one of them, and they're right, but I did have a Lexus for 10 years which I loved and I used to own three different Nissan 280s and 300s. I love the steering, the brakes, and the power! The sound and iDrive are real bonuses on top of that. Any current BMW can be had with the iDrive, but the sound is unique to the E9x M3s.
My car has been driven 21,500 trouble free miles.
Best of luck on your decision!