After spending a couple of days using various images available from the web site I decided to just follow the instructions at https://github.com/rern/RuneOS.
The build went fairly smoothly and at the end of it I had a functional system. I was super impressed at how easy the instructions were to follow and how smoothly the whole process went.
Now that I have the current best build of Rune I can properly evaluate it.
-Good SQ-really the most important thing at the end of the day
-The UI is very next level compared to Volumio. Breadcrumb trails in the library view, customizable playback and library screens, swiping on touch screen devices(didn't even realize I was missing this), auto generating random play list, and probably gobs of other stuff I haven't figured out yet.
-Easy adding of network sources. If something doesn't work out it actually tells me what and takes me right back to the screen where I can fix it.
The needs work:
-Speed. For most common tasks the UI is reasonably responsive, but when navigating into settings there can be huge delays from 10 seconds to literally forever. Would like to try a RP4 to see if this improves things, but on the 3b+ the delays can be a little daunting.
-DAC selection. It has both the Digione and Digione signature. In my opinion those are the only DAC options one should ever need, but I still use one Raspberry Pi with a Kali and Mamboberry which is not an option. Generic ESS 90xx works, but would Audiophonics 9023 be better? Hard to say since neither one is my exact card.
-Lack of a working downloadable image. I tried a few of the images and all were problematic for one reason or another. The images on the main download page are super out of date. The build process was easy for me, but I'm somewhat computer savvy and I happen to be running Linux on one of my computers. Rune is a project that is secretly kicking Moode and Volumio's ass, that most people won't be able to take advantage of.