USB vs Coax Is one better than the other?

I am wanting to buy a cable to go from Auralic Aries to a RME adi2 dac with a Teddy Pardo psu. I am using the stock USB that came with RME and a JPS Labs Superconductor digital cable I had lying around since 1997 it's the first generation from JPS. I can pan between the USB and Coax with streamer remote and find there is a difference in sound, not sure if it is the signature of JPS or it being a coax wire vs USB. The USB sounds more detailed and clean. Coax more analog and full. Both are enjoyable but just different. Should I invest in USB or Coax, thank you for your advise as I'm a little lost here.