I was choosing between Plex, JellyFin, and Emby some time ago and have settled down on Plex. However, the feature in Emby that I miss in Plex the most is the buttons that link to artists, album, movie, TV, actor entries on other databases (e.g. MusicBrainz, Last.fm, Discogs, MovieDB, TVDB, Wikipedia, etc) that Plex uses to scrape data from. (Such as the links sections shown on the image above)
Then I can know what database to contribute to in case I see missing data or incorrect data. Additionally, if the entry is appearing in one database and not the other, I can also contribute to add a new entry.
Now I can only guess what databases Plex might be scraping from when I see missing data and contribute to those, which is a waste of time as Plex refreshes databases once every hours (according to my guess).