This E10K just belies belief! For the price, I think this DAC/headphone amplifier is totally unbeatable. Yes, there ARE better-sounding units around, but you will have to spend at least double what this little beauty will set you back. It works seaml...Read moreessly with windows XP/7, is made to a very high standard and sounds great.
I use it to drive my Sennheiser MM 550-X passively to listen to both MP3/AAC and 24-bit 96Khz FLAC files via Foobar, and it's quiet, musical, and more than loud enough driving my Sennys. If you A-B this with an item like the Audioquest Dragonfly, then the more expensive item eclipses this with a slightly more refined sound, but as previously stated, this is more than double the price of the little Fiio.
Like other Fiio products, it really is a bargain, and I couldn't recommend this more highly. Get one now, before they realise they're almost giving them away at this price!