There was a program on discovery channel a few months ago called "Greatest Military Clashes" (I think).
One episode they compared the AK47 to the M16. And they found that that they are meant for different purposes. The AK47 is an Assult rifle that allows you to make your own cover when attacking. Whereas the M16 is a Rifle, It is used for accuracy at long-Medium ranges. It suffered in the Jungle because of reliability issues but also because the Vietnamese allowed the soldiers in close to "grab their belt buckle".
This could happen i the urban environment but superior tactcs and trainning can over come this slight advantage the AK47 has in CQB.