Notice the orginal 500 - 550 rpm rate of fire, thats what you get if you keep the gun clean and use the original ammunition.
And yes, it sure must be a real treat to shoot! I've heard it shoots better than the AK-47, being both more accurate and controllable. (Ofcourse there's also a 50-100 rpm difference in rate of fire)
I have to give the russians some credit for designing such a reliable and robust weapon but I disagree with their lack of inspiration...they could have come with a design of their own like the americans...even their famous smg the PPS during WW2 was copied from a finnish weapon...