ok, so i'm sitting here watch one of my favorit shows thought plex then i ocured to me that there is not a play all button in any of the players but then i got to thinking about and there is no playlist feature.
So there is a consept I would like to throw out there if at all posable to add to all the players. A playlist system that as it gets closer to an end of an episode it perbuffers the next episode or movie in the playlist. a few things that could be done with it is that you play whole seasons and even whole tv searies.
I don't know about any other clients, as I don't use any of them, but the Roku client already has a Continuous Play feature for TV shows that allows you to watch an entire season, or series. It works great! And the third party RaRflix Roku client goes one step further, and has an experimental version of Continuous Play for movies. It's not a Playlist System, but it's better than nothing. :)