Roon, Sonic Transporter and MRendu v. Air3

[Confused]

I only tried it with an Aurender W20 (2 month loaner from a friend) and probably to my inabilityfor objective hearing, i clearly favored the USB connection.

Well who knows?  There are no absolutes here, plus I always think that system synergy is very important, you cannot infer the performance and influence of one component onto every system out there.  It just shows the importance of trying things for yourself, and indeed being confident in what you like when others say different.  Who is to say who is right?   When it comes to your own system set up, then clear it is you that are right every time!