I'm quite satisfied with mine.
However,.... last night/this morning it played a prank on me that I've not experienced before. I couldn't get signal to the amp to save my life. Nothing had changed since the last time I used it. I followed the cables, checked everything, changed inputs at the amp, changed USB ports, checked cables again, tried the different inputs (spdif, optical, usb), checked settings in System Preferences; everything was seeming to be ok - still no sound.
Finally, I disconnected the DAC, and waited for a minute, and then plugged it back in. That did it. For some reason, it needed a reboot/restart.
Anyone else ever run into this?