both coaxial and optical are spdif so i think you referring to;
SPDIF = Coaxial input?
Toslink = optical input?
Well sound from the coaxial and optical so be no different, and I found the USB equally good when i did a quick test with my NFB-12.
Oops, You're absolutely right... I meant Coaxial input.
I'm a little concerned, since Audio GD has dropped USB from their ESS DACS outright.
User opinions are that Coaxial is best implemented, the Toslink seems well buffered in pictures tho.
anybody else.....? Bueller?