MicroDAC is a good component, and I am currently using it in my desktop setup, modded to accommodate OPA627 (suberb results), paired with a GilmoreLite.
However, my experiences with using it in a portable rig are somewhat different. The amp is battery hungry, and what's worse is that it drains one battery far, far faster than the other. So there I was, carrying around 4-6 9v rechargeables, Swapping the R battery into the slot for the drained L, trying to keep tabs on drained ones vs chargeds,.. it got tiresome after a while, and the rig was quite large to begin with (SR-71).
If I were to get a portable DAC now, it'd be one with its own rechargeable battery so I'd have none of that incessant swapping, at least once a day, sometimes twice.
But for a desktop unit, with its full +/- 15V swing, it sings baby!