AR has MOA accuracy in certain rifles, that's it. It requires a lot of maintenance to stay operating, and is very finnicky and tight-fitting(That's why it's accurate). The AKS line of rifles, the originals, were made of sheet, and scrap metal, along with the only wood Mr. Kalishnikov had lying around. They had, and still have extremely loose tolerances, and that's why they are so reliable. You can literally fill up the receiver with sand and it still operate. This gun will not have it's reliability beaten in our life-time, it probably never will. Now, accuracy is a different story. Precision shooters don't like them. It all ties back in to having loose tolerances, and it gives each shot inconsistency. But, you can still hit a plate at 75-100 yards with all 30 rounds if you tried, so that is killing accuracy. They were built to kill the enemy on the battlefield, so they have the accuracy to do that.
AK hands down.