I used MythTV for decades. I really loved the “raw” digital output of the music player. It would casually hop from 44/16/2.0 to 96/24/5.1 between songs and my amp would decode it. I even contributed a small patch to make the visualizer work with 24bit audio.
The live TV hardware accelerated deinterlacing was really good too. TV recording was super reliable.
The TVDb lookup was a tad glitchy. It turns out that it didn’t include the year in the lookup. I wrote a patch that did it (and improved my metadata lookups heaps) but never made a PR.
I jumped to Plex around 2020. Mostly for things like streaming to my phone so I can have my music on the train. I believe Myth was better for HTPC, but Plex isn’t too far off.
I’m not a fan of Plex audio. Every time I try to make it do AC3 passthrough or skip the OS mixers, the whole thing breaks.