Personally, I would prefer something that can output to studio monitors as well as accept 3.5mm and XLR microphones (at work I have a Focusrite Scarlet 18i8 and like it very much.) If it is just pure headphone amplification that everyone wants, then all four are good choices and it is up to which price point everyone wants. In any case, the only DAC problem I have ever had came from a mini-USB. From moving the unit, the connector dislodged, so I would say go with a full-sized USB if you tend to move the unit on your workspace. Best of luck!
