The joys of open source. If one day they want to close up, someone else can continue on what was open. Nice to have an evactuation plan built-in to such services in case things go rouge or the devs simply need to make decisions for themselves over the customer.
Yeah, seeking is still a bit flaky. But subtitles work great for me, at least when using the Web and Roku clients. I got a better experience in some corner cases on the Roku client by making sure that the filenames ended with ".en.srt" so Jellyfin correctly associates them with the English language.
That's not such a big deciding factor for me, and I am happy to pay for Emby. When I evaluated my move off Plex, Jellyfin was not nearly as refined as I would have liked.
I might give Jellyfin a go at some point. Since they all are children of XBMC, I assume that the metadata format is the same, meaning all my thumbnails, posters, trailers, subtitles and so on can stay in the filesystem next to the media and it'll "just work" with Jellyfin.