Since vi/Vim and Emacs are pretty close in terms of what they can or cannot do, productivity with these two editors comes from experience in using it.
In my opinion, being a programmer it won't take you long to get the general idea about Emacs once you start using it. Others can only say so much, you got to try it out for yourself to know it.
As for me, I use both. It's like taking more than one weapon to a war, use the right one in the right circumstances. ;)
