I'd say Obsidian is very similar to Zim. Zim is probably the closest thing I looked at before deciding to make my own thing. I wanted a few things that Zim did

I'd say Obsidian is very similar to Zim. Zim is probably the closest thing I looked at before deciding to make my own thing. I wanted a few things that Zim didn't offer, such as a quick PDF viewer, bib/reference entries, audio notes (embeddable), and space repetition for term/definition pairs. I realize these needs are highly personal and they will be plugins that you can enable/disable. I didn't love the interface but it wasn't a deal breaker.