I'm using #ed (the "original" text editor) to periodically edit a file I'm interested in.
I'm not sure I'd "endorse" it, and it's hardly "friendly", but I'm not finding it TOO bad at the moment. Will I switch over to ed permanently, I wonder?
BTW, it helps a lot when combined with #rlwrap.
I'm actually contemplating (although not seriously) making a vim-like editor using #guile.