W4S DAC2.
Took me a while to get operation sorted -- having more to do with locating and copying my iTune files to a HDD than anything to do with the BDP-1 -- but once I got it working it is quite an amazing device. And this from someone extremely skeptical of anything to do with computer audio.
Only weaknesses are in the stock software to select music and play it on BDP-1. I used MAX for starters and it is fairly rudimentary, clunky and non-intuitive, but it works. So now I use Gnome player on a netbook, which is free to download and does not even require an Internet connection. The interface is much better, more intuitive and more versatile. When I get my iPhone next month, I will use that.
The other weakness is when you detach HDD to add more music to it,and then reattach to BDP-1, the BDP-1 takes a while to update itself. The more music on the HDD, the longer it takes to update; therefore, I only update the HDD every few weeks or when I have added a lot of new music.
Aside from the foregoing, this is sonically and operationally a breakthrough product, with great customer support from Bryston.And you don't need USB/SPDIFconverters, USB cables, special software, etc.
Neal