My observations after a good deal of experimentation:
1. Vs. Meridian Director, less glare in vocals (a godsend), but more unforced natural detail in the vocal, and vocals do not stand out with artificial highlighting, a typical digital fault. A big step up from the Meridian, can't turn back.
2. Best sound with external headphone amp and run with the volume control bypassed*, especially in the bass control. I never thought my old Headroom Max here could sound so great. (But the internal amp is pretty fine also, actually.)
3. Nice improvement in refinement using the USB 3.0 port from my computer: even less digital glare, a sense of balance with all musical objects in balance and no stress.
4. While actually good with generic USB cable, a better one really helps. I'm using an Audioquest Carbon with their micro adapter.
5. Overall, most of the enthusiasm about this thing has been validated in my testing. Well worth the cost for the DAC alone. A cure for digital stress with very good insight, the holy grail of high end audio. Just sitting back going through my favorite youtube stuff and can't pull myself away from listening.
6. Gripes: lack of a standard full size USB 2.0 port is annoying. You can't even get AQ high end usb cables with micro B plugs! I would much rather have this than the crossfeed stuff. I even question the need for all the optical inputs, most input sources have USB output. I also wish the USB input was on the same side as the RCA output plugs.
It looks like a Medusa with the cables going out from both sides of this thing and looped over my desk.
7. Fine headphone matches: Fostex TH900 (great synergy somehow), Oppo PM1.
8. The sonics get more awesome with break-in for 12 hours or so, in the bass especially.
9. But, despite my gripes, the bottom line is (like the Beach Boys said) I can hear music, sweet sweet music...
10. A few years ago I had a Playback Designs MPS5 and an EMM CDSA and I like this DAC better (no pain, more refined).
*Press+Hold crossfeed button while turning on the unit. Do NOT plug in headphones to the unit in the mode.