Newish product

No first hand use info but he was booted from the computer audiofile board some time ago.

This is interesting. Checking into all, thanks guys!!

If you isolate the noise generated through the USB cable via Galvanic Isolation or similar (USB Disrupter) what would give better sound quality Bluesound Vault 2 Streamer or a MacBook via USB, both into external DAC?

Generally, galvanic isolation is used for devices such as laptops.  Their power supplies, when plugged into A/C, are not good and can cause major hum/buzz from 60hz a/c.  This is where galvanic isolators are valuable.  If you don't have this problem, it's better to avoid the isolator modules and focus on a really good USB cable. USB interface is highly dependent on timing of clock signals and you don't want anything in the middle that could cause timing problems or degradation of signals.  If you want to try to improve USB audio, your better off getting a USB reclocker, such as Wyred 4 Sound "Recovery" product.

auxinput, sometimes I use a MacBook and I don't experience and and buzz or hum which I guess is good. I don't quite understand the timing or clocking issue you mention. How would I know if that's a problem? I'll need to research and learn a bit.