I used Universal Media Server for 3 years, not knowing about jellyfin actually. UMS was a most of the time non-functional piece of crap. Refreshing the library was a pain and always felt that it required restarting services and devices on both sides and a blessing from the local priest. Then comes the frequent disappearance of the server itself which again requires service restarts. Then the mid-movie playback stops or stutters. Not recognizing the subtitles and again requiring service restarts. I spent more time fiddling with the app, holding it together with duct-tape and sticks rather the watching media through it. It is a very unstable and unreliable piece of software.

Then came jellyfin, and as a breath of fresh air, all my problems were gone. In maybe 2 years since I switched to it, I can count on my fingers how many times did I have to fiddle with it for some reason. It just works, in the most common sense of ways, no crashes, no discoverability problems, nothing, just pure stable performance, I cannot emphasize enough how much of a chasm exists in quality and usability between jellyfin and UMS. While UMS feels like a piece of early alpha software that was abandoned, jellyfin is the rock solid , actively maintained alternative that got your back.

Universal Media Server is just bad software.