Anyone who is serious about taking notes doesn’t use Apple’s Reminders app. Or at least, they don’t use it to store endless snippets of information (Reminder is fantastic for shopping lists, though). Note nerds use nvALT (OS X), the tricked-out version of Notational Velocity customized by Brett “I just built this. Again” Terpstra, in combination with Dropbox or Simplenote (iOS).
And Brett’s latest version, 2.2, is near enough release that you may as well grab it and use it. Hell, Brett himself says that it’s “more stable than 2.1 is right now.”