I'm a big Emby user with a large library - trying Jellyfin and it just doesn't compare, feels like a cheap knock off. It crashes quite often requiring a reboot of the service, the client apps hang a lot and the plugin support isn't the same.
Jellyfin user with a relatively large library here. I am not having any crashing or hanging issues, did you use the Docker image when you tried it? Can't really speak about the plugin support since I haven't used Emby.
Haven't tried Docker, ran it on both Windows and Linux, on the same machines that Emby ran on. I tried it for a while but it was too unstable and I kinda gave up - switched back to Emby.