Computer Audio Asylum: USB DAC vs. UA5 by olympionex

I hope this question hasn't already been anwsered... I searched through the forums and didn't see anything.

I'm considering two options for constructing a computer transport, and I was just wondering if anybody had any relevant experience.

In both situations, I am strongly considering using a mac mini running either linux or osx as the computer.

Considering that I already own an edirol ua-5 however, I cannot figure out if it would be better for me to use a wavelength USB DAC (the brick) or the ua-5 feeding into a benchmark DAC1. Are either of these options bitperfect on either osx or linux?

Are there any clearly better solutions (less expensive options are helpful as well)

Thanks,
Matt