Well I got them for three days and I can't say that I'm impressed. They are quite sibilant so I have to EQ down higher frequencies, wide soundstage I only noticed in attached test cd, bass is good but not that great and I'm also noticing little cracks in sound in background. But that is not very noticeable. Sound isolation is fine and comfort is only average.
But it's not my place to review yet, I only have them for three days and I never tried them with proper source. Only with my onboard "HD" soundcard, hi-fi and cell phone.
I am going to buy Asus Essence ST for them so I hope that this will improve my experience by lot, otherwise they are not worth it. So far it's comparable experience as with my 40€ Logitech X-230 repro
I'm also not sure whether it's a good step to go for Essence ST, which has some built-in hp amp if I'm already thinking to buy some external amp like for example E7 for them later. Or maybe some lower Asus soundcard and go straight for some amp as well? I read some reviews and they wrote that Xonar Essence is quite better than it's lower class brothers and I might find its different 3D features quite beneficial for my movie and games experience. Hmm
I don't put many hopes in improvement after burn in, but as I don't see big difference between 128/320Kbit mp3/FLAC, it may be indeed just matter of poor output hardware.
Hope that Asus sc will be enough for this. Don't get me wrong, I quite like what I hear so far, but it's far from 400€ WOW experience and as I have already tried it with our hi-fi which was quite expensive at the time and It was only slight improvement against PC, I remain quite sceptical