Jellyfin-Kodi gives fast and automatic library updates - no waiting 5 minutes for ‘update library’ on large collections - new content appears automatically. Also some nice QoL improvements like synced progress, slightly better metadata fetching, automatic subtitle fetching
I personally prefer JellyCon as it’s more lightweight and works smoother for low-resource devices. Jellyfin-Kodi has more features and deeper integration with the library.
The initial setup took a bit of work, and there are definitely some quirks, but all-in-all it's worked for me really well. I would wholeheartedly recommend both Jellyfin and Kodi for anyone interested in a HTPC/home streaming setup.
[1] https://github.com/jellyfin/jellyfin-kodi [2] https://github.com/UnicornsOnLSD/finamp
(Don't use the Jellyfin Connect addon, it's different and I wouldn't recommend it)