In that case, this leads me to the next question, i.e., how to best compare DACs?
Firstly features - do you need remote volume control - do you need USB input - do you want XLR - do you want a high quality finish and faceplate?
Since there are many good ones - I'd recommend to audition a few. You can start by reading reviews and see which DAC's have the most persuasive specs, preferrably with excellent jitter rejection/immunity and a highish number of positive reviews from respected reviewers. Narrow it down to a few (all will be good) and begin listening (several offer return policies) Frankly, I don't think you will find night and day differences - so your personal tastes will be the deciding factor.
Jitter immunity is probably the single most important technical factor in a DAC (given that othe rspecs will generally be excellent) ...it is well known that all audio interfaces carry at least some jitter....how much of this is audible is debatable.