ive been using kodi (xbmc was better moniker) since google killed sagetv. i recall attempting plex, but it seemed to lack some open/extensibility (its been awhile).
i have a side project i want to make as a modular plugin generating a cable layout with original air orders and networks/channels... kodi seems most optimal, but ill admit its been a long while since i looked at plex.
Used Kodi for a long time (even had an XBMC) and switched when it became more of a chore keeping Kodi updated across multiple devices than it was worth - along with wanting to play easier across more devices.
It's unfortunate, but just the UI customization that I loved Kodi for couldn't keep me on it over the lack of reasonable server/client architecture, minimal headless scraper capability (you can do it, but it sucks), and the general attitude of the forums getting very...angry/pissy?
One of the things that really put me off Kodi (as a long time user as well, I also had an XBMC xbox) was the mentality of "it shouldn't be easy, there shouldn't be any setup wizards. It needs to be difficult to configure and get working because we're l33t haxors!" in so many kodi forums and affiliated people. They wanted it to be hard to set up and use because it made them feel smart, it was absolutely ridiculous.
As soon as Plex got their UI to a design I liked I jumped ship and haven't looked back.
for ease of use, ive separated kodi from the scraping (mediaelch!), forcing it to go local for initial data load.
ive only really forced updates in kodi for necessity, which is almost never.
youre right, the lack of client/server architecture sucks donkey balls. forced me to jump through a lot of hoops to get a default, auto configuring install for house machines.
i wish kodi would just incorporate something like jellyfin natively... they work so well together anyway.