The AK has a deserved reputation of reliable cycling under any conditions. When you're looking at an armed bad guy 10 feet away, that's kind of important
At that range I like 12 gages.
I have trained extensively on both in my prior life. The AK is a vastly inferior action for urban combat relative to the AR, primarily because it is bloody slow to use even in the hands of a competent soldier. An AR15 can put more rounds in more targets faster in the hands of a competent user than any assault weapon of its time, which is the genius of its design. It allows extremely rapid and precise target engagement, something that I have learned to appreciate. Incidentally, these weapons (and several others) have been put through performance metrics that measure this type of thing, and I have been involved in some such studies, though a cursory googling is not finding much in the way of published data on this point (not surprising, being pre-web studies). If the primary objective is to hit a lot of targets fast, the AR is your action.
As an aside, we never had any reliability problems with the AR actions out in the field, even when pretty filthy. But then, I never used Viet Nam era ARs with the defective Viet Nam era ammo that gave them their (undeserved) reputation for unreliability.
On the other hand, the reputation for poor accuracy of the AKs is not entirely deserved either. The Finnish Valmets (excellent AK actions), for example, have a rack-grade accuracy that easily rivals the M14, though neither is as precise as the AR action (which is intrinsically far more precise than it needs to be for a military weapon).