I upgraded from my original Magni/Modi to a JDS Atom, and wanted a DAC that would fit better with the Atom and look better too (hey, this hobby isn't just about sound :P).
I bought this instead of just sticking with an SDAC primarily because of the bluetooth input, which is quite helpful for me as I run a laptop+desktop setup with switchable monitors and Synergy sharing keyboard and mouse. I can't yet pipe low latency audio easily between the two computers into one DAC (suggestions welcome), so I use this to switch between the two machines.
The USB interface isn't perfect - occasionally it'll freeze up and I'll need to disconnect it, power cycle it, and try again. It's not bad, but it definitely isn't perfect. Then again, I've had minor issues like this with many other DACs as well.
I was disappointed that the OLED display on mine wasn't white, it was more a light blue colour, so doesn't match white lights for anything else. I was even more disappointed to get burn-in on the OLED display on mine (as I wanted to leave it on - I guess there's a reason why it defaults to auto-off). Maybe if they make a bluetooth-enabled D10s with that delicious amber display...
Sound quality-wise, well, it's a high quality DAC. It's uncoloured and transparent, I can't tell much difference between it and most other modern DACs.
Oh, and the remote is a nice touch.
Loving' the new Sennheiser HD 6xx open headphones from Drop. I have a small (but mighty!) sound system in my home office: Aiyima T-10 Headphone pre-amp to Aiyima T9 Pro power amp to Sony SSCS5...