Biggest upside of Plex for me is the fact that you can set up secure streaming from anywhere with basically a single click. With Jellyfin, that is much more manual.
Besides that, I think some people may like that Plex has its own set of TV Shows & movies to stream, though I'm certain that those are ad supported. (Haven't used that feature & have moved to Jellyfin)
i dont have a desktop or a server that can run this stuff constantly yet. but is usenet still good for the "discussions?" i thought there were better free versions.
If you have the time to seed a lot then private torrent trackers can be just as effective for finding your ahem... linux ISOs without the cost. Usenet is most useful for people who are worried about repercussions from their gov for seeding (as many count this as "distribution" and it carries more weight than simply downloading)
I would be torrenting with a VPN with multihop, and seeding is a bit iffy in my country becuase you cannot be charged here for downloading, but you can be charged with seeding.
Usenet is a bit more work to setup than bittorrent, but you will be able to find lots of movies and TV shows there without having to seed anything. Unfortunately, you have to pay for access to good indexers if you want to download more than a few files per day.
As far as I know, there's still a strong but small community on Usenet for discussions still
As far as server/desktop stuffs, many have had decent success running them on things like old laptops and raspberry pis to decent success. Won't be as powerful, but if it's just you and a spouse and maybe kids or something it should be just fine