I bought the x2 as my 1st audiophile headphones after reading loads if reviews and I absolutely love them. I even have invested in to a JDS labs c5d which should arrive next week in the hope it makes them even better. (Portable for versatility as I am planning of future buys)
I listen to a lot of different types of music and play PC games, and it really seems a nice all rounder, which is what I was after. Bought a v-moda mic as an addon for voice coms which was a nice bonus for gaming.
For music I can hear things that simply was not there before, the sound stage from them seem very good to my untrained ears.
Admittedly I don't have a lot to compare it too right now (cheap senn gaming headset that broke and a crappy siberia headset, apple ear buds that come with phone, so nothing spectacular). These headphones have really piqued my interest though. I have always enjoyed music but lately I have been listening to more than I have for many years, simply because of how much I enjoy they sound if the x2's.
They build quality is great, maybe a little heavier than I am used to but not to the point it is uncomfortable. I think i payed £180 from a site named after a rain forest, an italian one where they where much cheaper than the uk site.
The only downside is to the bank account as I am now interested in a set of closed cans, a set of iem's and something very neutral sounding...