I think that doing a usability study on both of them would reveal that the usability people would run shrieking from the building once the basics were explained to them. On one hand, you peck at the esc button like a hungry chicken to do anything useful, with the other, your hands play twister on the keyboard "pinky.... CTRL... thumb... ALT... index finger... S".

That said, I've never been even remotely tempted to move to anything besides Emacs, and at this point, it's ingrained in my fingers, so non-Emacs things really piss me off.