Who cares?
I got racks of both so I can fire nearly any variant I want at anytime
Ergonomics, accuracy, weight and recoil go to the M16 and it's variants...
Resilience, ruggedness, reliability go to the AK and it's variants.
And since I venture that the VAST MAJORITY of the members here have not fired these full auto at length I will point out the following:
What sucks: The M16 sucks when trying to clear a 'stuck' casing in the chamber. I've had to pull a gun completely and issue another one just because of that. In a filthy environment, the M16s are a real liability. I've had them malfunction in sandy environments and muddy raining environments. Mostly due to failure to load or extract.
The AK is way better when clearing the gun under fire.
When a shell gets stuck in an AK you just put the rifle's buttplate on the ground and kick the charging handle down with your boot (all battlefield expediencies). If the brass body stays in the chamber then you have to ditch the rifle, but it is easier to clear a jam than an M16. I've had to do this 'boot' clearing with the charging handles of M1 Garands in dirty battlefields as well. (make sure the barrel is pointing away from your face
) and in the case of magazine fed weapons, dump the mag first.
The M16 is safer when firing questionable ammo. If the charge is too hot then the slender aluminum magazine blows out the bottom of the rifle (of course the soldier should STOP firing immediately and return the rifle to the armorer). For the record I've never seen this anywhere when using ammo that *I* issue.
When firing prolonged bursts, the AKs get super hot (all guns do, but the AKs burn my hands). the M16s were designed for better thought towards heat shields and protection of the shooter. Also the Chinese TYpe 56 AKs have that stupid metal pin that traverses laterally through the lower wooden forearm, which ensures that you burn your hand when dumping a 30 round magazine. If you don't fancy the thought of carrying a scorching hot piece of metal around after firing, then the M16 is safer for the shooter.
Recoil: The AK is a shoulder killer. The M16 has that buffer spring to absorb a lot of the recoil - "Bang! ....Sproinggggggg!" Also with recoil buffers the guns are much nicer to shoot, but then these silicon/polymer recoil buffers are a recent innovation and were not available to soldiers for decades.
Both are excellent guns but both have their strengths and drawbacks.