I bent my pick on my windows box (W7 Pro 64 bit); even though the machine recognized the DAC and I got the drivers installed fine, I couldn't seem to find a way to get sound of it. I didn't give it a huge amount of time, though, since I have a Mac Mini to use as a music server.
The Mac was literally plug and play. I think I had to change an option to select the right output, but apart from that, no muss, no fuss. I installed Amarra and it, too, was plug and play.