Pros: powerful headphone amp, good DAC for the money, dual headphone outputs
Cons: a bit too loud
For less than 200 dollars, there's not a lot to complain about here. The MX1's amp sounds quite good and powers K702s without trouble, and the DAC does a respectable job and sounds even better when hooked up to a separate amp.
One problem I have with the MX1 is the gain is a little too high. With most of my headphones, I can barely turn the volume control past the 8 o'clock level, which causes some channel imbalance. As a preamp, though, I don't have this problem, probably because my headphone amp allows me to further adjust the volume.
I fully recommend the MX1 as a convenient, one-piece solution to get great sound out of a computer. Although it's not the last word in sound quality, as a solid-state DAC/headphone amp combo, it's hard to beat in terms of value.