If you work with plain text, as I prefer to, then you probably try out different text editors from time to time (or, you know, constantly).
For a long time I used plain text files via nvAlt (as McCallion does). I miss plain text files. Then I moved to Simplenote. Then for a short time to Evernote. Then back to Simplenote. And now I’m just using Apple’s Notes.
In between all of those I’ve tried dozens of text editors.
Notes is incredibly useful and while it doesn’t support plain text files it is perfect for nearly every thing I do. For now.