To clarify, viper for Emacs includes most of vi's modes, so the editing experience can be very vi-like. [1] What happens is you tune the environment on a scale from vi to Emacs, with the one extreme being almost identical to vi and the other keeping its core key bindings but freeing up the ones needed to fully take advantage of Emacs Lisp, which is arguably more powerful than vimscript.

Yes, thanks for the XMonad intro, I really can't wait to try it.

P.S. I think we have some friends in common and may cross paths at the l2l. :)

[1] As johnswamps points out in the neighboring comment, to get vim features (not just vi) you may need vimpulse as well.