Benchmark DAC1 vs. Headroom Desktop?

The DAC1 would be hard to beat.

I have both, and can honestly say that the Benchmark's DAC is much better than the Desktop's built in DAC (and I have the Max version of the DAC). The DAC1's amp is good too but has a somewhat different sound signature compared to the HR Desktop. I personally prefer using my DAC1 to feed an external amp (Headamp GS-1). Since it sounds like you're thinking of a one box solution for now, if you get the DAC1, you'll get a no-compromise state of the art DAC along with a pretty good amp, which you can later upgrade, if you choose, with an external amp.

To my ears (using Grado SR60 and AKG701 cans), the DAC1-USB with its internal amp sounds slightly forward and possibly slightly dry, but has excellent lateral soundstaging, and plenty of dynamic range, detail and overall resolving power. By contrast the Desktop DAC+amp combo sounds somewhat constricted in lateral soundstage, and somewhat veiled with less resolution, especially in the highest frequency ranges, which to me lack the zest or sparkle that the DAC1 has. On the other hand, the Desktop does seem to have a more "spacious" and warmer sound. Curiously you might think the Desktop would be easier on the ears compared to the DAC1's presentation, but that is not the case - I preferred the DAC1 which to me was less fatiguing over the long run. It still wasn't perfect until I decided to mate the DAC1 with a Headamp GS-1, which slightly smooths and warms out the forward character of the DAC1 amp and adds more "air" and better imaging to individual instruments but lets all of the detail and resolution of the DAC itself through. So this is my impression of these two products -- one caveat is that with both, you're really comparing a DAC+amp combo rather than the amps themselves. I did not try feeding the DAC1 into the Desktop - perhaps that would have changed the sound but in your case, it would be irrelevant since you seem to be mainly interested in the one-box solution. Again, assuming you really need a DAC, I would say go with the Benchmark -- you can always add a "better" amp to it later. Don't waste your money on the built-in DAC in the Desktop -- it's just OK, not great.