Just noticed this thread. I’ve been commenting about jPlay for iOS on a Roon thread.
A couple of years ago, I tried jPlay. I liked the sound quality. However, I was put off by it not being gapless with my streamer.
After several years as a Roon user, I recently moved back to UPnP because I wasn’t at all happy with its sound quality. Inspired by @audphile1 and thinking there was a workaround to make it gapless, I tried jPlay out again a few days ago.
The gapless workaround didn’t work out, but I was so blown away by the sound quality that I have decided to go with jPlay anyway.

