For the DAC:
The DC-1 uses TWO AD 1955 chips in dual differential mode for astonishing specs - see the Audio Precision reports on the DC-1 page at Emo's site. Over 200 pages of detailed test results!
These are the same DAC chips used in the brand new Cambridge Audio 851D, selling for $1,500 - they call them the Cadillac of dacs.
For SQ, I extensively compared the DC-1 to the ESS Sabre 9018 (as used in the Oppo BDP-105), the Sabre 9016 used in the BMC Puredac, and the Wolfson 8740 used in Cambridge Audio's Stream Magic 6 as well as the PS Audio Digital Link III.
In each case, on my very highly resolving system, the DC-1 had none of the sibilance the others exhibited, at no loss of detail. Great bass, reflecting the large toroidal transformer they use.
For digital sources, I use my Macbook Air (unplugged from the wall) for Hi-res files up to 192 into the DC-1's USB input, an Apple Airport Express through toslink for streaming MOG from my iPad or iPhone, my TV out into the Coax input and my blu-ray player into the BNC input (through a coax to BNC adapter). All work flawlessly -no distortion, noise, clicks or pops.
I connect my Thorens turntable through a phono preamp into the analog ins, and connect my powered subwoofer through the analog outs. Again, all good.
The remote is an extremely well made chunk of aluminum that gets the job done. A remote is a must have for me.
I'm not primarily a headphone guy, instead preferring to listen to my Magneplanars in my rather large listening space, so can't comment too much there except to say that my Sennheiser HD-600's sound great to me! I will say that the BUF-634 analog buffers are used in other high-end HP amps.....
I originally used the DC-1 through a preamp, but quickly realized I didn't need it with the DC-1's capabilities. Sold.
By way of background, I've been at this for over 40 years, and have recently owned very high-end components, including Balanced Audio Technology, Audio Research and Dynaudio components.
For me, the combination of performance, features, price, 5 year warranty and 30 day no questions return policy can't be beat. I've tried, but have concluded that you'd need to spend over $1.8K to get more overall, including the Benchmark, Grace or NAD Dacs. No DSD, but I'm not interested!
At the Emo site, you will find a forum that has over 60 pages of user experiences with the DC-1.
A no brainer, IMO.
Of course, YMMV, IMHO, and maybe even WTF!