I purchased one already
I only have around a hour on it so far. First, the fit and finish is excellent ... I would imagine on par with some more expensive gear. I found the imaging to be excellent, the sound to be warm, yet accurate and detailed. I was very surprised.
My den is 12' x 13'
Source: Mac Mini/Firestone USB Headphone/DAC
Speakers: Klipsch KG 4.5's (95db sensitivity)
For the price I think it's a great bargain! I wish it had another set of RCA inputs for a CD player or such, but for a small package I understand. A remote would be nice too. I have yet to use my AKG headphones with it yet, but would imagine them to sound just as good.
Here are my photos: