I had a 6x illuminated that I got for $100 or so. Light gathering is excellent, the way it mounts to the side rail is very robust, and the scope itself is built like a T-54 tank. That being said, the length of the objective tube on mine interfered with the rear iron sight, as in actually physically touching it, which made mounting it a real bitch. Also, be aware that putting a scope on your bullet-hose AK does not turn it into an accurate rifle, just a bullet-hose AK that has a scope on it now. If your rifle shot 4 inch groups at 100 yards before, this will not make it shoot 2 inch groups unless its you and not the gun.
That being said, they are excellent for the money. Sometime I'll get a 4x that mounts to the gun correctly-- I think the 6x I had was for a Dragunov, not for an AK, although it still mounted fine.