I've started to use emacs, and I've found out that while the editor-specific features of emacs are better than those of vi, the text-manipulation methods of vi are better than those of emacs (and easier on your control-pinky!).
It seems that viper-mode, a marriage of the two best parts of each editor, is the ideal solution for someone that wants a complete editor.
But before I start investing my time learning the vi commands in the emacs environment, I'd like to know why it doesn't seem like many people use viper-mode. Is there something I'll find out after using it a while that will cause me to switch to plain emacs or vi?