There's a bunch of editors installed with the Oztivo image; most people get familiar with one and then use that. Aside from joe, there's ed, elvis, nano, pico, vi/vim, and maybe others.

ed is probably only there for programs that need it. pico and nano are possibly best for new users, because they have possible commands listed, avoiding research to find out what arcane key combinations are needed to perform some simple action.

Emacs is missing. This is good ;-).