On a purely personal basis, I always liked the simplicity and reliability of the AK design. KISS - Keep It Simple, Stupid.
Not only is the AK a reliable weapon, its cartridge has the same ballistics as a .30-30 Winchester round and has VERY powerful, knock-down power. I tested one recently at the rifle range and it is a reliable and accurate weapon within 300 yards. I was using just its standard iron sights with adjustable range on the rear sight and had excellent results.