I have AK & AR style rifles and both will get the jobs they were designed for done. The AK is a heavier rifle, uses a larger/heavier round and is as tough as nails. It's more than accurate enough for self defense situations out to 200+ yards (can place shots into a paper plate sized target) and they are half the price of an AR. The AK is lighter, uses a smaller (more ammo per pound) bullet, has more options available and is more accurate at ranges beyond 200 yards.
For someone needing a weapon that will stand up to tough use and/or abuse on targets no longer than a city block or two distant, the AK is a better choice. If you feel the need for a rifle that can hit 1" targets at 400 yds you can easily customize - if you have the money - with every option or caliber imaginable, you'd be better off with an AR.
"... Americans... we want a safe home, to keep the money we make and shoot bad guys." -- Denny Crane