I have 8 ARs and something like 20 AKs. In the hermetically sealed and safe civilian environment, an AR is just fine, maybe better from a standpoint of weight, ease of use and depending on the case accuracy. My wife has confiscated my SP1 clone. But judging guns like this is like judging people, you don't judge em while they are at leasure with no stress, but you measue by how they act when the poop hits the windmill. I'm sorry, but in adverse conditions it's AK all the way. Yes any weapon can be made to malfunction, but what does it take to get it back up and running? AK gets crud in it and stops working, pop the cover, rack it upside down a few times to knock the foreign junk out, and you most likely back in business. I've had ARs choke on primers popped out of cases. Had to take em appart to get the primers out of the disconnector slot. Can't happen in an AK. ARs like to run wet. AKs run wet, dry or anything in between. All is well for your AR if you have a nice supply of lube you can get at, otherwise, your screwed. Then there's the goofy things ARs do, like shattering bolts and eroding gas ports. AKs don't do things like that. If I had to pick one weapon to have, it'd be my Yugo M95 in .223. (if we're talking stricktly AK/AR. otherwise, I'll take my FAL. )
For proven long term reliability in adverse conditions, AK has it hands down, period.