Having both, I can tell you IMHO the MTPC are the better sounding earphone. Bass is just as punchy and controlled, mids are more detailed and lush, highs have better extension and control. Soundstage and instrument separation are also slightly larger with the Coppers. The only thing the X10 has going for it is its small form factor.
Again these are my opinions using both out of my p3+. Have not compared unamped. Hope this helps
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Edit: Also I have had mine from the original release and have not had any problems with build quality. Not to say you wont, but I'm very pleased with the quality of both my Turbines.
Edited by Enanthate - 5/16/11 at 8:26pm