I always bounce around between Emacs, Vim and TextMate I've tried IDEs but their typically not native code, have shitty keybindings, are slow as dog crap and need to be custmized with entire plugins rather a few lines of elisp, python or whatever.

If I had to choose between the 3 I'd go with Emacs and I don't know how much more productive but well in the range of "enough". We code everyday in mostly the same place so learn your tool and enjoy it.