AK47 vs M16?

I have been watching some programs on the military channel and "Guns of the world" and they pretty much agree that the AK47 is a superior ault rifle over the M16. These are opinions from military people who use and test weapons. If this is the case, why doesn't the U.S. military either adopt the AK47 as the Nato weapon or develop a new one based on the AK47. I would think the military would want the best there is. I know U.S. pride is a factor.