I always CTLR + F these threads for Jellyfin, because most people I know use Plex and don't even know Jellyfin. Are you happy with it? I've been using it for like half a year now and am pretty satisfied.
I primarily use it via the Android TV app, and it's been a pretty smooth experience for at least the last couple of years.
Other than that, the things which don't quite work for me:
- Jellyfin is useless on my Android phone. Media with 5.1 sound is severely broken, I can only hear the background noise, the actual dialog is just barely hearable. Could be a config issue on my end, but I haven't found out what the issue is. Now I just download stuff and watch it in VLC. Works, but it's not the best UX.
- Sometimes when I add a lot of content, the metadata gathering seems to be stuck. I can refresh the libraries, refresh a single item, but nothing seems to work. Then, after a couple of hours, it magically starts to pull all the metadata and is done in a couple of minutes.
Else - I enjoy it very much. Even donated some money, which I do (too) rarely for OSS.
- Web player: Video works, audio is broken.
- Integrated player or External player: Unable to load media info from server
no idea why it can't load the media info from the server, might have to dig into the logs...streaming via PC or TV works so it's not a network issue.
I think the Jellyfin UI is easily understandable for users, but what you might have to be prepared for is supporting them with technical issues. Jellyfin has apps for Android[-TV], iOS, webOS, Windows and probably more. I gave my dad access to Jellyfin and he had some issues with it related to Chromecast and his TV. On my end I can't use the Android app because I run into audio issues (could be my fault).
Jellyfin is awesome when it works and I really love it, but I've had to dive into the logs quite a few times. Sometimes it was my fault, but other times it's noticeable that Jellyfin is a smaller OSS. Stuff breaks, especially edge cases.
AFAIK you can just install Jellyfin and point it to the same libraries which your Plex uses. That way you can test it for yourself without bothering the people who use Plex. It might add some pictures, but the rest will be fine.
I think if you already have a Plex setup which works and you're happy with, I'd stick with that. I chose Jellyfin because Plex seemed too commercialized to me and I heard some things about it I didn't really like. But most people I know use Plex over Jellyfin, the only people who use Jellyfin are the ones who I managed to convince to use it :)