USB Galvanic Isolation?

They are all about the same. :)

It's actually really sad it isn't always included in the DACs themselves. The main benefit is they prevent ground loops, from either the audio outs or the digital interface.  The first is very easy to hear, sounds like humm.

The second is not and causes additional, measurable jitter.

Unfortunately not all DAC's are happy with isolators.  My Mytek is not, and it does suffer from ground loops depending on the connection.  I have to just use other sources.

Most DAC's however will work just fine with the cheapie isolators.

Thanks for that. My AMR DP777SE has a fair amount of isolation on the DAC end to decouple the PC hash and some de-jitter protocols to boot. My DAC also doesn't need a the cable's power leg - does it make sense to get a signal only USB cable? I see that Sablon has one...and JCAT with separate legs anyway.

I use a Mac Mini as a server and use a Shunyata Omega USB cable to my LampOzator DAC. The Omega USB cable made a huge difference in improving the SQ. USB cables do make a difference.