Now that I have 923 notes in HTML files on my hard drive, I can do whatever I want with them. My current plan is to import them into OneNote because they have good app coverage across platforms and they just released what looks like a pretty solid API that lets you import and export notes.
Maybe I (or somebody else) can write an importer for Standard Notes to make it easy to switch from Apple Notes?
 Notes not syncing across devices
 Search not working at all on Mac
 Moving subfolders of notes in the app makes the notes completely disappear
If you ever decide to build an importer, feel free to submit a pull request and I'd be happy to merge it.