When comparing Plex vs Kodi, the Slant community recommends Kodi for most people. In the question“What are the best media center programs?” Kodi is ranked 1st while Plex is ranked 3rd.
Ranked in these QuestionsQuestion Ranking
Pro Supported on many devices
It's pretty hard to find a NAS or STB that doesn't support Plex.
Pro Accessible via web browser
A modern web browser is enough to get everything Plex has to offer.
Pro Added lots of media databases
Metadata for media files will automatically be updated by using media databases. This provides posters, movie trailers, descriptions, information about actors, etc.
Pro Lots of plugins available
Pro Can install on several devices
Apple TV (jailbroken), Mac, Windows, Linux, iOS, Xbox, and more.
Pro Open source
Not a freemium software.
Con Needs registration
You need a PLEX account even if you use it on your local LAN.
Con Proprietary software
Con No gapless audio-playback
Plex still does not support gapless playback of audio files such as mp3 or FLAC.
Con Playback error: This server is not powerful enough to convert video
More hardware requirements on Plex due to a useless/non-intuitive transcoder. When using lower spec hardware (eg SBC) Plex will not transcode or play HD+ videos. When compared to other packages (eg Jellyfin which transcodes nicely using FFMeg), Plex falls short on video playback and transcode settings to get videos to play (fastest/lightest option still fails).
Con For some devices it requires them to be jailbroken or similar
Con Terrible navigation
Menus over menus with dozens of submenus.
Con No official AAA addons for streaming services
It does not have any official AAA addons and fully relies on the community which result in often broken packages/addons.
Con Poorly optimized
Often not a fluid experience.