Forward of the grip, they are pretty much identical in size. The real difference come with the grip portion of the frame. Since the EMP was designed to fire the 9mm, the grip is shorter front to back than a standard 1911. That also means that things like the trigger, firing pin, extractor, plunger tube, grips and magazines are also smaller.
The EMP does fit in the hand a little better, IMHO. VERY accurate for a 3" pistol! I have one, and it's my carry gun. I used to have a Kimber Ultra CDP, and I prefer the EMP. Much easier to shoot.