Plex is better at looking up show names, has an easier UI to set up more complicated stuff like hardware acceleration, has better clients across a variety of platforms… the only reason I’m using Jellyfin over Plex at this point is because I anticipate Plex shitting the bed. If you’re on Plex, there’s no reason to swap from it, and honestly if you’re comparing the two as a newbie, Plex is still a much easier option.