For me, Plex would often end up having audio drift lag and it was annoying as fuck. It’d start fine, then the lag would gradually increase until you changed encoding back and forth, then gradually increase again.
Jellyfin just works.
That was enough to get me to switch and not look back. I’m also rid of the bullshit plex login that I never cared for, and also of their push for whatever “recommended” stuff is supposed to be about.