In short, the Ak was designed around a mag built to last the life of the weapon, the AR built to shoot the mag and throw it away.
The actions are equally reliable - and who makes them equally culpable in getting them right. Century is pretty well known as being the tarnish on the AK's reputation, lots of new owners have complaints of poor quality construction. Cheap ARs, not so much, what's forgotten is that you MUST use full power ammo - cheap import fodder does NOT have enough gas power to cycle the action.
What stacks up is the written press on the AK always saying how reliable it is, but they mistakenly call it that. It's durable, able to keep functioning despite being damaged. The AR suffers from bad press and ignorance, being called a jammomatic and "defecates where it eats," mostly by those who believe anecdotal stories with no real understanding of what actually stopped the weapon.
Since AK's have really good mags, they seem ultra reliable. AR's, drop a mag loaded on the feed lips, and you have problems. It's taken 45 years to wake up and blame the magazines, finally we have Pmags issued in Afghanistan, and there's little problem to report. The guns themselves, millions have been made, and millions of soldiers who've used them are equally impressed they keep running no matter what.
What colors the conversation is that the grass looks greener on the other side, let the fence sitter beware. Your neighbor has gophers, rocks, and places needing to be trimmed by hand, too. They're just in different places, you have to know where to look, and very few Americans are gunsmith level armorers who design actions. In other words, no clue.
Just look at what they drive.