я вот на этой стороне :

"Let`s start with interfaces; the obvious choices are USB, Firewire, Optical, and S/PDIF. What is your opinion on any of these interfaces? What if any, are the advantages or disadvantages of one over the others in terms of resolution, jitter, etc.?

I believe the interface itself doesn`t really matter as long as the transport is done correctly. There are rumors that one offers slightly less higher or lower rates of jitter but that all depends on implementation. USB has become popular because everyone has a USB port. Most USB DACs out there are really just external sound cards with a simplified output. Personally I`ve chosen an optical output so that I can decouple the PC from the DAC circuit altogether."
Pete Davey

http://www.positive-feedback.com/Issue41/ca_rankin.htm