Plex beats Kodi in two areas for me: DVR service, which Kodi doesn't provide, and remote playback. Plex will transcode videos on demand to smaller storage sizes, and store them in its iOS and Android apps for offline viewing (and their Roku app is far superior to Kodi UPnP). When it works, it works great: like having my own version of YouTube TV/Sling TV, only without any of the DRM/non skippable ad nonsense. But it doesn't always work great.

The reason I pointed out Emby is that it has all the features Plex does that Kodi does not. Kodi has some stuff available by plugin but matching the features I require from Plex has never been possible.