In the interest of science, I will purchase a glass toslink and do a comparison between my modified DVP-S7000 and my computer as a source, switching between the coax and the toslink input. That's as close as I can get to a true A/B. If USB sounds better to me, it is better. If not, I will go back to the cd route. All I want is the best sound from a given source.
I believe that if Peter thought that the signal coming from his cd transport was better he would stay that route. However, to his ears, the USB route sounds better. He's a passionate audiophile who just does stuff to get the best sound, like most of us here. I would do the A/B tonight if I had a glass toslink on hand. Best Buy don't carry none.
I'll post my opinions on the matter when I get it all set up. However, regardless of source, the DDDac itself sounds exceptional when stacking 16 of those battery-powered noisy dacs all together and having the signal come straight off the chips with no I/V conversion. I can't go wrong either way.