anyone have experience with both the Schiit Gungnir Multibit and PS Audio DirectStream

I have the Gumby and do not experience the relay click between tracks. It does click when I first play a new source, but not between tracks. This would be a function of your streamer. I have used a Pi, Node 2i and Sonos Connect, no clicks between tracks. 

I've done some research and I've been told that  the relay click is used to switch between different "sample rates and bit depths".   So if you're listening to an album that was all recorded (digitally) identically, you will get no click.  If there is any difference, then you'll get the click.  I think you can also get the click is there is a short period of silence between the tracks (when streaming) that is not presented in the same format. 

this is correct - the clicking is pita...  bad when you have a playlist that has tracks of different types

There are certain transports, like the Cambridge, that if you put a playing disc in pause, the Gung clicks constantly until you resume play.  A design feature, I gather.

The only clicking I’ve heard is from the Bluesound Node for most but not all mp3s. Irregardless of DAC.
This made me convert them to #8 compressed .flac.

Clicks gone