I borrowed from a friend of mine an USB DAC - Beresford TC-7520SE Caiman
Hooked it up with the NC with non-powered usb hub and it worked instantly and sounds excellent playing FLACs

I can't compare right now the sq between 3.5mm/DAC because I used 2 lousy speakers ( Altough I would say that the channel separation is way better with the DAC )
But when my E7 arrives I'm planning to do an E-MU 0404 PCI / NC 3.5mm / NC + E7 / NC + E7 + L7 battle
I'll be comparing the relative SPL between all of them using my Behringer ECM8000 before I start so it should be an even field with the MS-8 controlling the volume

I just love Android , almost everything is possible