Hi!, I am no expert by any means, not am I a very knowledgeable audiophile.
I have had this Unit in my living room for the past few weeks, it has been used to power my Elac B6 set.
That being said I used it with a few headphones: HD800S, HD 6XX and OPPO PM-3.
It works well, has a lot of power for a small unit. I found I picked up a bit too much black noise with it for the 800's
I also don't think it's the most open sound, it keep things tight.
I got this unit for the footprint (nice, small and discrete) and for the versatility (remote, fiber and usb)
I recommend it If you use it as an all-in-one solution, not so much for headphones only.
I'll answer any questions you have, don't hesitate!
James