FYI: the wadax combo along with some $150k reference loudspeakers were in one of the worst sounding rooms at last years Axpona according to multiple reviewers/sources.
In the past, years ago, I preferred other dacs to the at the time best dac MSB offered for quite a bit less money.
as i mentioned above, it’s not trivial to do a proper compare, and it starts with a sorted out room. when i go into a room at an audio show and don’t care for the sound i don’t associate the gear with that perception other than the most slight data point. maybe it’s a Friday and i return on Sunday.
I would never use the faulty usb protocol into a dac. Every review I have read and in my own experience, usb sounds worse than i2s or Ethernet.
of course, those who pay attention would know the Wadax does not use the USB interface, it uses the Akasa optical interface. it can use USB, but it’s not ideal.
OTOH i happen to strongly disagree with your USB comments relative to my time with the MSB Select II. early on i was using the MSB Ethernet interface, the Renderer v2, then i tried the MSB Pro USB interface and that was clearly better. it’s a mistake to generalize about digital interfaces. it’s all about execution. and a moving target.
now with the Digital Director, MSB might have a different ideal interface. don't know about it.
and reviewers rarely have state of the art servers for the dacs they review. so i would be careful what you read. better to investigate for yourself at the top level. maybe at more modest level gear USB is less effective than Ethernet. that might be true, but i don’t personally know about it. again, it’s about execution more than dogma.