This flies a bit in the face of the author's "The sync breaks. The company sells out and dies" point and the simple beauty of a text file. I find that Obsidian.md is just one step above a text file.

Simple daily notes, which are automatically organized into year and month folders. (Tip: Set the date format to YYYY/YYYY-MM/YYYY-MM-DD)

The Sync feature works great, but no reason you couldn't do this with just git on your own.

Plenty of built-in features (Plugins, ToDos, etc...)

Cross platform apps.

Markdown

Free. The sync feature is $4/month. Worth it for me.

They also have a one-time $25 payment to get early access to beta versions and a VIP discord channel.