I have been listening to the uLink for a couple of months now.
What I can say is that it sounds much better than the digital out from my Transporter. I know that its an apples and oranges comparison. I'm using the Schiit Gungnir as a DAC. I switched from Squeezbox to USB with JRiver. Very happy with the switch.
The reason I bought the uLink is that I needed two digital outputs, a BNC for my Gungnir and an optical for my sub-woofer. The sound of both have improved by not a small margin. Deeper tighter bass, cleaner bigger better defined highs and mids. All good. I now feel that with the network Squeezebox I was polishing a turd. I'm now running the uLink off a 9v battery. Not sure about the sound differences with a battery, but its a no brain-er. When I bought the Gungnir I stayed away from their USB option, and bought it without. Glad I did.