I've used the following: Vepr, Saiga, Kreb's KTRs, Bulgarians (SLRs and Arsenals), Chinese (Polytechs and Norincos), Vectors, original Zastava Yugos, various parts guns from China, Bulgaria, Poland, East Germany, and others, Galils, and Valmets.
Best AK?
Accurate but heavy, Vepr.
Best overall gun, Tromix converted Saiga. I'll put one of our Tromix guns against any AK from any country or any custom build from any smith. The base Russian gun is excellent, runs around 2 MOA, and Tony can convert them to any configuration that you can imagine.
I'm not a typical AK shooter. I like to use mine in competition as well, and I do pretty good. I've got a lot of rounds through various AKs, and I'm dead serious when I would take a Saiga against anything out there.