Aside of Plex, there'a also Emby, and Kodi.
Each have their + and -. Here's a comparison between the 3 [1].
(Disclaimer: I use Emby.)
[1] http://www.htpcbeginner.com/plex-vs-emby-comparison-with-kod...
It's open source and has most of the features that plex has.
> "Purchase Emby Premiere and receive additional bonus features such as Cover Art, Mobile Sync, Cloud Sync, and free Android apps."
Incidentally, the paid features seems to include most of the things that would make me consider a media centre installation, which would seem to make the open source version mostly uninteresting to me at least.
I have both running, but unfortunately, the Emby server just burns resources like there was no tomorrow, and you can't really compare the UX at all, hence using Plex.
This looks clean and simple to manage and would cover my needs perfectly.
At this point I'm willing to give up control over my media for convenience though so maybe my opinion is invalid. I remember spending hours organizing my mp3 collection. Forget that.
edit: Apparently XBMC is now Kodi so it actually is a direct competitor.
Would also have been interesting to hear what they view their edge as, as plex is already a pretty mature and powerful codebase, where as this appears to be very new. (I'd guess being open source would probably be their main edge right now)
Well, if you're looking for an open source alternative to Plex, there's Kodi already.
Besides: https://www.plex.tv/plex-pass-pro/ looks both hilarious and sad.
IIRC the reason Kodi (back when it was called XBMC) switched to GPLv2 is because they got forked by Plex who didn't give back. I wasn't able to find a source on this though.
https://en.wikipedia.org/wiki/Plex_(software)#Plex_Home_Thea...
Plex apps are 100% closed source as far as I understand.