Whichever you can get cheaper. If you go with the ODAC, I'd get something like the Wyrd much sooner. I get noticeably different results based on the quality of my USB output.
Alternatively, a friend and I both prefer the Geek Out 450 as DAC over the ODAC. I'd consider going that path. I use mine to a Krell Klone at work as a temporary DAC and it was a step up from the ODAC.
Sounds congested and less resolving straight out of my old macbook air and other notebooks compared to my desktop. Once I get it back, I'll test my macbook pro and surface pro 3 USB out with and without the Wyrd