USB is horrible - you don’t want that.
Asynchronous usb has come a long way to date.
Even Thorsten Loesch of AMR/iFi fame, recommends usb over s/pdif despite his newly designed s/pdif Purifier :-
http://www.digitalaudioreview.net/2016/05/ifi-audios-spdif-ipurifier-debuts-at-fujiya-avic-spring-20...
"....... Loesch says this new unit isn’t for everyone. He still recommends end users go with USB should it remain available to them."