A jaundiced point of view:
vi (not vim) is a professional necessity. You always have some form of vi easily available, no matter what the environment. You can be in vi when in emacs, you can be in vi to build bash commands in unix-land.
Even Microsquish has to support vi (although they do a good job of hiding it) because of gov't and corporate compliance with published standards.
In my opinion, if you are in a hands-on job in a busy environment--not a hothouse flower confined to one fancy rig in a development environment, or in academia--knowing a lot about a fancy editor is a job handicap. Don't learn all the fancy tricks in vim or emacs, and don't develop a bunch of macros to make the editing environment bend to your will. It's an enormous time sink that gets in your way when you attend to different machines that you probably can't justify in a factory environment.
Read Bill Joy's paper--it is a very competent, perhaps even beautiful, engineering exercise in editing plain text very, very fast. Parito's rule applies here: 80% of the fruit is in 20% of the baskets. Editing plain text very very fast is the crux of editing competence--all else is optional--and sometimes hurtful.