It's definitely worth learning enough to use, just in case your preferred editor isn't available. I tried it, but couldn't get used to switching modes, I kept

It's definitely worth learning enough to use, just in case your preferred editor isn't available. I tried it, but couldn't get used to switching modes, I kept messing up my file and having to backout and fix things; so I memorized a subset of vi that would let me get any editing done that I absolutely had to and went back to using emacs for regular use. Note that the default version of vi is not always vim, some systems use elvis or other vi clone, some of which have different advanced features and keybindings; for use when nothing else is available, concentrate on the basic vi commands.