For me the main things that matter are
- it works on both desktop (for taking longer notes from reading) and android (for short notes on quick thoughts / things to remember)
- the underlying file format is just plain text
- sync can be achieved with syncthing
- Changing the title of a note and then backing out of the note does not save the title change; I had
to switch focus to the body of the note before the title change would save
- Backing out of a note exited the app instead of bringing me to the previous view
- Backing out of a sub-setting view exited the settings instead of bringing me to the parent settings
view, so even looking for a setting that might help the first two annoyances was also annoying
Some options for syncing on mobile: Obsidian sells a first party syncing solution, which I hear works well:
I do git syncing on Android via termux (It works most of the time, except when git decides to shit itself every now and then on my tablet):
https://forum.obsidian.md/t/guide-using-git-to-sync-your-obs...
I can't vouch for it because I don't have any iOS devices new enough to support it, but supposedly you can use Working Copy to sync via git on iOS:
https://forum.obsidian.md/t/mobile-setting-up-ios-git-based-...