Just to throw my 2 cents in. Overall Plex works great, remote access, sharing libraries and even automatic metadata gathering and tagging. I did mourn the loss of Watch later but hey.
My biggest lately is my music library, with about 8,000 albums it seems everyday half the collection goes missing and then i have to re-scan the collection and it eventually re-finds everything. This only just started over the last month or so.
I use the Fire tv app and the roku app and both work fine they play and display what they think is in the data base.
and i and running plex media server on a intel NUC PC with a quad core possessor and nothing else on there w 8 Gb of Ram , so not an anemic system by any stretch. am on version 1.18.8.2468 on the server.
Any body else seeing these quirky issues.