I own a Cary 303 and a QSonix server. Running the digital signal out of the Cary into either my Canbridge dacMagic or my Benchmark allows direct comparison to my QSonix run thru the same DAC. Someone out there might hear a difference, but I certainly don't. And, believe me, I tried to. The functionality (GUI & associated software) of the QSonix is great and I will never go back to a stand-alone CD player.
Marty
BTW, I've written about it in these threads so you can search for QSonix to get my (lengthly) description of this unit. It's pretty expensive, but I'm sure that there are good alternatives with a similar GUI. If I were looking at a lower price point, I'd check out the new H-P touch screen PCs, for starters.