If you pay $2.48/month: markdown and a lot of text editors, to-do lists, spreadsheets, encrypted attachments for your notes stored directly in Dropbox or Google Drive, themes, 2FA, note version history, etc.
Minuses:
They could improve the user interface
You have to pay for what I said before.
Who or what problems you think it works especially well and poorly for
I use it as my personal knowledge management. From book quotes, to meeting notes, as a to-do list, to writing texts, etc.
Standard Notes is my choice.
Plusses:
Minuses:
Who or what problems you think it works especially well and poorly for