Sorry, but referring to Plex as an example is misleading, especially the Plex ATV App is, compared to Emby, a pain in the ass. In Plex are every useful function unnecessary buried in some submenus, e.g. subtitle or audio selection before playing and so on. Also is the little available backdrop support by Plex, covered by their GUI. Damn, I want to enjoy my backdrops and not their damn GUI
Yes, the Plex App has definitely more direct play and subtitle capabilities then Emby but the GUI is so f...king designed that I dropped it as soon as Emby met my requirements. From the GUI design I love a lot of the fine Kodi surfaces, Aeon Nox is my absolut favourite, but I switched from the Kodi surface to the native Emby app because I didn't get the theme music to run on Kodin nor the rotating backgrounds; and I love this features.
So, EMBY isn't perfect but compared to Plex it contains the better user experiance.