I currently use Emacs Org mode for my zettelkasten knowledge system, which uses .org
files (I use this plugin: https://www.eliasstorms.net/zetteldeft/). I had originally used markdown, but it has several issues and inconsistent versions which led me to switch to .org. It seems that many developers with zettelkasten systems have also chosen this setup.
I love the UI and Vim keybindings for Obsidian and would love to try it. It would be awesome to have support for .org
files (or at least a way to convert them) in addition to markdown.