If there is one thing that a like about the RS4 is that it has some great colors.
Candy Blue, Bright Red, Ferrari Yellow etc. M colors have a tendency to be a bit controversial and an aquired taste. Anyhoo, looks-wise the RS4 is ahead of the M3. The M to me looks like a regular 3er whos owner dug deep into the accessories catalogue. Everything looks tacked on, rather then the E46 , where it looked as if that car was designed as the M3 first and regular 3 series after.