"If emacs is not installed on a system, I use sed."

Bill Joy (creator of vi) once said that if he sits down on a foreign system, he reaches for ed [1].

To be fair, both emacs and vi have "magic exit incantations", though if you have emacs perhaps you have a menu in GUI mode. If not, C-x C-c is really not any more memorable than :wq! The vi one at least has an obvious mnemonic ("write quit") but either way, you need to know an arbitrary sequence of keystrokes.

[1] http://xahlee.info/comp/interview_with_bill_joy.html