Personal Knowledge Management Systems (PKMS)

I've been using Obsidian for a while, but recently, I've started considering that either of these grant me Obsidian's main advantage- your knowledge base being portable- while also being FOSS software. (In particular org-mode also gives me access to some things VimWiki would lack like support for things like images.) ...Oh, and apparently org-mode can be exported to loads of other things through the glorious program that is Pandoc. Loads of Android apps that work with org-mode as well, so you can, in fact, sync everything between pretty much everything!