After a night of drinking a couple weekends ago, I literally almost got into a fist-fight while debating Barry vs. Emmitt. (Yes, yes I know...this is a sign that I should stop before finishing the entire 12-pack, but I'm still in college so I get some slack.)
Anyways, for several of the reasons that have already been mentioned, Emmitt was better...by a freaking landslide.
Here is my favorite way to put it...Barry was a better runner, Emmitt was easily the better running back.
Barry killed countless drives for every drive he made with a spectacular 60 yard TD run. He couldn't block, couldn't run up the middle, couldn't get you the first down on 3rd and 1, couldn't punch it in at the goalline, couldn't concede when a play is blown and just take what he could - instead choosing to prance around and suffer a 6 yard loss, couldn't lower his shoulder and absorb contact to gain an extra yard or 2, and most importantly - COULDN'T WIN. Simply - he couldn't be everything Emmitt was. Everything a great RB should be.