No. The "X headphones" (I assume you mean the MDR-X10) are disappointing - congested, bass-driven, flattened highs, and the fit/build is funky (in a bad way). The QC15 are more balanced (they have boosted bass, but it isn't boom-boom all the time), have better top-end extension, are more comfortable, offer better isolation (who'dve thunk it?), have much better soundstaging, and so on - they're an easy suggestion over the X10.
This thread is almost a year old, and OP never returned after posting it...it's a zombie.
(I wish there was a halloween themed smiley for times like this).