They are very similar headphones. I find the COP to be more engaging. It was the mids that turned me off of the M50 and really took me out of the music whereas I have no issue wit the COP mids. Not sure about the volume issue. A huge COP selling point for me is comfort. I never cared much for the feel of the M50 on my head. While burn in loosens the sound up a bit the signature does not change. It really comes down to different strokes.