I mostly use Ubuntu, so I'm not short of options. I've tried to get used to Emacs but I think I have to admit defeat: it's simply too much. On the other hand, both Nano and Text Editor are OK for a quick bit of editing but aren't really environments that I want to work in for any length of time.

For the moment, Micro seems to offer what I need, giving a nice balance between simplicity and usefulness. I'm maintaining my notes in Dropbox so they're available on all my devices and because they're just plain text I can always find something to edit them if I don't have Micro to hand.