"So re-clocking the digital signal from the S/PDIF vs a USB converter, would there be an advantage to one over the other?"
Yes. Both are establishing a new Master Clock, but the reclocker must resample the data. There are minor artifacts with doing this. Even the best resampling hardware is not perfect. The USB interface on the other hand does not resample. It does not change the data at all, making it superior with better SQ.
Both are excellent however, particularly when powered from my new Dynamo power supply. The difference is actually small.
Steve N.
Empirical Audio