The functionality is great, and like you said, it can play pretty much anything. But the UX feels like it's stuck in the late 90s, and the following are more ugly and painful than they need to be:
playlists
streaming
converting file types
It can do a ton of stuff, but none of it is particularly intuitive, because the UX sucks. But it works great at the basic functionality I need, which is playing pretty much any video format.
i use musicbee for audio. vlc for video. musicbee is the most like mediamonkey used to be and free. got into vlc because of its better support of the unusual video formats