I have only used Plex very briefly before I moved to try Emby then Jellyfin. Granted I am not a heavy user of a media server - basically no one else in my household uses it, and I don’t have a lot of content, but I do use sonarr / radarr with it.
The moment Plex put me off was when I realized a Plex Pass was needed to add transcoding capability. What are some of the reasons people like Plex better than Jellyfin, other than those who have been using Plex forever and are just too lazy to explore other options?
Plex has a client app on just about every single media player out there and they have a simple single sign on solution.
So I personally run both Plex and Jellyfin, Jellyfin for myself as I’m willing to put up with some of the hoops I have to jump through and Plex for everyone else who just gets an invite email, creates an account and suddenly has access to all of my content on every single device they own.
Once jellyfin has reliable apps on every App Store and a simple way of getting non-tech savvy users onboarded I’ll move everyone over to jellyfin. Until then, it’s just for me.