DAC diminishing returns

For the record I stream with an Ethernet connection to a raspberry pie 3 with a digihat and a Toslink connection to my bifrost.

This HAT and toslink are a weak link. You’ll get much better quality output from Pi through RCA coax (or better with BNC if DAC has it) from a different HAT like this

https://allo.com/sparky/digione.html

Another option is HiFiBerry DIGI2 Pro

To get the most from the Pontus you need a streamer transport like a Lumin U2 and the Denafrips DDC like an Iris or Hermes running I2S to the Pontus, otherwise you are driving it or even the Bifrost in 2nd gear.

Does the significantly higher cost justify what might be a marginal increase in sound quality?

Do this test and see if you get it right 100%. If not ... no need to spend more money.

https://www.npr.org/sections/therecord/2015/06/02/411473508/how-well-can-you-hear-audio-quality

Of course if you just feel this itch to pamper yourself and get some nice new gear, that can be satisfactory all by itself.

What is your budget?  I would recomed you buy a DAC from a dealer with a return exchange policy and try for yourself.  

With Denafrips dacs I own 2 currently and in the mk2 version there is no micro skipping issue ,idont even know what that means.   Look up pontus mk2 , or Terminator 2 dacs read some reviews ,  if going to buy state what is your Max budget  this helps , as I mentioned the$4500-$6500 isthe sweet spot 

and they are made over seas Holo springs, and Denafrips  you would have to pay much more to = this   And both nowhave repair centers inthe U.S

 but are very dependable , they all sound different abit Multibit - R2R dacs are the original type dac chips and sound a bit smoother , going up the chain mola mola dac is great at$14 k  ,and of course DCS dacs but are $$ ,which have their own custom architecture.