They're about the same to me, although you wouldn't know it by my lopsided collection with all but two shooting the 7.62x39. They each have their merits as has been mentioned already. I'll probably get a few more AKMs and at least one AK-47, then start collecting AK-74s more aggressively. In the AK-74 world, there really isn't as much variety to choose from as there is with AKMs. You're pretty much going to get a SAR (Romanian), Tantal (Polish), Saiga SGL series (Russian), or one of the many Bulgarian variants.
Pittsburgh Steelers fan till the day I die, and then some.