Hey, I just got a Venue 8 pro and I'm using it to drive my Burson Conductor. My experience with it has so far been pretty good. Using the desktop, you can run apps like Foobar2000 to get bit-perfect playback (not something you can apparently do in Metro.) I'm playing files mostly over wi-fi on my home network and I've been pretty happy with the performance / lack of jitter with USB audio out /etc.
That said, I've noticed that the power output from the USB connection is pretty low. The Burson Conductor uses a Tenor USB chip and seems to work pretty well. However, I also have 2 DACs which use the CMedia USB chip, and neither of them can work with the Venue 8 pro because it doesn't output enough power. I think they might work if I used a powered USB hub, but haven't tried. So, net-net is that you results my vary especially if you try to go direct from the USB out. But, if you can get it working it's nice.