You can read man pages in emacs easily, but if you want to replace the man command with emacs you have to play a few tricks:
A script for starting emacs in man mode:
#!/bin/bash emacs -nw --eval="(man \"$1\")" -q -l ~/.emacs-man
Where .emacs-man is your setup for reading man-pages in emacs, one thing you probably want in this is:
(setq Man-notify-method 'bully )
To open the man page as the only buffer.
My requirements: vertical split, goto-line, unicode.
I am currently using this where I cannot use emacs or if I need to edit big files. It supports most of the features I use, but it is acting weird sometimes.