The next best solution is Tap [0] (disclaimer: I am the founder).
I had a few revelations related to these kinds of notes:
In order for them to get collected, they need to be collectable from anywhere (if not pen and paper: email, sms, browser, whatever).
The note system should accommodate many different types of information: links, tasks, events, transactional information, formulas, etc. Plain-text doesn't work because over time you'll develop more and more sophisticated systems. Without a standard notation system you will lose the ability to process and analyze your notes and the information they contain.