I signed up and paid for the 5 year Standard Notes plan yesterday but by the end of the day I had requested a refund under the terms of their 30 day trial. The app was far too slow on my (still fast) iPhone X. Plus whenever you use anything but the plain editor on the phone, you lose a lot of system text exiting behaviour: selection was wonky, spell check and corrections are missing.
I shared feedback with my refund request and the person noted there is room for improvement with the mobile app.