I just picked one of these up instead of a FiiO Q5 to replace a dying Alpen E17 at work. Glad I read the reviews before making this decision, I'm very happy with the xDSD. In fact, after about 2 hours of listening I actually enjoy it better than my NFB-11.28. The Burr Brown DAC is more musical than the ES9028, and the filters (3D+ & XBass are pretty great). It's definitely not as powerful as the NFB but for office listening it doesn't need to be.
Makes me think of selling the NFB in favor of a Micro BL