I've just installed a Wiim Pro (non-Plus) to replace an Allo DigiOne Signature as my digital transport, coax-out into my Hegel H160. The software available for RPi-based digital transports has always been a bit hit-and-miss, and the final straw for me is that Librespot - the library that many of these products use to implement Spotify Connect - will not support Spotify Lossless. That's been confirmed and it's a legal/licensing issue, which seems unlikely to change.
I decided to switch to the WiiM because its suite of software is much better, and I'm only using the digital out anyway. I can't say I've noticed any audible difference on my system (Hegel + ProAc D20R). I would like to do a blind test, but that will have to wait for now.