in my experience with my own guns, i would have to rank the russian makes at the top of the list. they were the originators, had the tooling, resources, and engineering to back them up.
from there, i would say bulgarian, hungarian, yugoslavian, a toss between the egyptian and chinese version, and then romanian. not knocking any of them, because they all had their own pros/cons.
i believe there were also some knock-off copies produced in other countries with backing from russia or china.
you also have the "improved upon" AK's, such as the Galil from Israel, and the Valmet and Sako from Finland, among others.