Both my Metric Halo DACs utilize Firewire ports, but it seems MH is now offering an 'upgrade' path to USB integration with 1ms latency drivers to support both Windoze AND Linux.
For my purposes, I'm fine using Firewire, and I don't have to worry about paying premium prices for boutique, audiophile USB cables. As far as FW cables go, a GoldX or Oyaide d+ still does the job quite well, and at low cost.