I don't think there are any bad ones as far as functioning is concerned?? And reliability is what AK's are good at. My 1st one was a Norinco and when I 1st took the dust cover off and looked inside of it, I felt sick looking at how crude and cheap it looked. (I ordered it through Shotgun news, so I didn't ever look at one before buying.) Well, after many thousands of rounds and more abuse than any 10 rifles should receive, it's still as reliable as ever. I consider it my main defensive rifle in fact. It was bought new in the late 1980's.
I've since bought 2 others - both Chinese also but not Norinco's - at least I think they aren't. I never pay any attention to what they are honestly. They are just AK's.
One has a thumbhole stock and the other a sporting rifle buttstock such as a normal bolt action rifle might have. Both obviously manufactured in response to Slick Willie's assault weapon ban and his definition of what constituted an assault weapon. The later has a forged receiver. From a design standpoint, forged is better than stamped, but from a practicality point I doubt it makes any difference to the majority of shooters. It would take more ammo than you or I would ever want to pay for to wear out a stamped receiver.