What I really like about Obsidian is that it stores your notes as plain text/markdown files on your computer. So you always have access to them, even without Obsidian itself. Markdown is also a fairly common format, so it shouldn’t be too hard to move them somewhere else later.
But your concerns are still valid and I generally also prefer free open source software.
Obsidian is closed source, so once the company dies, no one can modify the app. Joplin on the other hand is open source.
What I really like about Obsidian is that it stores your notes as plain text/markdown files on your computer. So you always have access to them, even without Obsidian itself. Markdown is also a fairly common format, so it shouldn’t be too hard to move them somewhere else later.
But your concerns are still valid and I generally also prefer free open source software.
The app may be closed-source, but the data is all markdown, which should be easy to move to other apps.
At some point I realized that the solution to this little problem is Emacs org-mode. It’s just sitting there waiting for people to use it.
I’m a l former emacs user of ~10 years and I could never get used to org mode, so it’s definitely not for “normal” people.
Additionally, in modern times being emacs bound means no decent mobile client, no web interface, and mandatory roll-your-own sync and backup.
There’s a few friends I know who swear by org mode up and down, but it’s a considerable effort for most people to use it.