I use Simplenote for journaling and creating itineraries for my wife and I (publish as a webpage and send link). It's great. Robust export options too. I used to use Obsidian + iCloud sync daemon to facilitate continuity between my Windows desktop and my Macbook, but I started getting sync issues on Windows and a couple BSODs due to how the iCloud daemon handles timestamps. I picked up Simplenote and it's been working flawlessly. Very underrated IMO.
I tried this before and I can’t remember why I ended up not using it. Maybe because, even though it supports markdown, notes are stored in a database and not directly on the filesystem?
I think Notational Velocity (MacOS) still supports syncing with SimpleNote while keeping notes as separate files locally (though I've not used it with Simplenote in several years and could be wrong, switched to a hacked together SyncThing + iCloud approach that mostly works).
I need note sync to work across Linux and iOS, and sometimes Windows. So actually I've ended up with the same solution of a hacked together iCloud/Syncthing Windows VM bridge.
The only thing I'm really missing is the ability to share notes with my wife. For this I've put together a really hacky script that looks for presence or absence of `#shared` and moves the note to or from a subfolder. It works okay, but not as well as Simplenote's built-in sharing did.
According to my notes (using Obsidian), there was not support for linking to other notes which was a deal breaker for me. I'm curious if this has changed, but not curious enough to install it.