I bought one last week and I'm happy with it. I'm using it with my iPhone 5 and Shure SE846's.
Output volume is much higher than from my iPhone.
The A200p gives a bit better sound, but mainly a different sound than my iPhone. A bit more separation, slighty better bass response, but a slightly darker sound overall due to the Wolfson 8740.
I don't believe this is the best headphone dac/amp around for €299,-, but I like its portability. You can slide your iPhone in your pocket and attach the A200p to your belt. This way you can use it as a remote for volume, pause, play and skipping songs.
More questions? Shoot!
edit: just changed the filters of the SE846 from neutral to bright and sound improved quite a bit. More air and better balance (in combination with this DAC).
Edited by Moody - 2/22/14 at 6:46am