Hi Ichigo,
Depends on what you're looking for. The M22's will give a more accurate sound but should be paired with a sub to get full range sound. I have the on/in wall version of the M22 (the W22) and they sound amazingly detailed and accurate IMHO. The M3 provides a bit of a 'bump' in the mid bass region making them sound 'fuller' on their own, so could be an interesting option if there's no sub in the equation. That being said, you can probably get the same type of sound from the M22's by boosting your EQ a bit in the right region. My personal choice would be the M22's with a sub. Hope that helps a bit.
