From my limited knowledge of streaming, it’s seems the consensus is USB seems better than coax?
It's been a few years, but I did a shootout with all the various digital output types when I had a bunch of gear that allowed it.
My findings, (and this strictly MY preference) were:
1. Tie---I2S and Firewire (very rare to find)
2. AES/EBU
3. Coax on BNC
4. Coax on RCA
5. USB
6. Glass Fiber
7. Toslink
This was probably 4-5 years ago. Has the USB interface changed? I found it to be one of my least favorite? Just curious, because I've never looked back towards USB after this...

