I know a lot of people are having issues with the DAC/Amp, but for me, it's working well. There are no left/right balance issues, and the DAC/Amp itself is not making any weird zip-zap or static or humming or jitter noises. My apartment is in a city, so if there is hum, its not audible above my noise floor. The Amp is quite powerful and can drive my headphones (AKG7XX) very well. It remains connected to my computer 24/7, and is always on. It gets a little warm, but that is expected, and it doesn't cause any issues.
That said, the power supply for the unit is VERY VERY loud. It makes a periodic clicking humming noise, and basically makes the unit unusable. But instead of returning this, I am planning on just buying a new power supply for it. For those having clicking or noise issues, my advice is check the power supply.