Ranked in these QuestionsQuestion Ranking
Pro Like MPV with better GUI and settings
It's like mpv, just more user friendly GUI and more settings available via UI.
Pro Doesn't black out other displays when doing full screen
It can black out other screens if you want, but out of the box it leaves your other displays alone.
Pro Support for lots of codecs
Supports lots of video codecs, like mp4, mkv, etc, and lots of audio codecs including opus
Pro Runs on MPV so it's scriptable and runs any MPV script.
Tip: if you're doing a lot of cropping and slicing of videos and you thought the new quick tools in Finder / Quicktime Player are a great improvement, try setting up IINA with slicing.lua and some keybindings for navigating your video + setting the slicing positions.
Make sure your ffmpeg command (in slicing.lua) is set to copy the original codecs and that it's using your GPU.
Con Black out other displays when doing full screen
Con Will not correctly play 10-bit h265 full HD video files
Try skipping forward or backward and the playback fails.
May crash unexpectedly, while clicking on something in the subtitles section in the right-hand panel, for example.