very hard pick
as in real life, the Ak versions of airsoft are more rugged than m series versions. The V3 can take 400fps wihout having to be modified to a reinforced shell
m4 series are also great, handling to me is better, accuracy is better (depending wat u gots in the gun) and more accesories can be added on.
however, now that i have the aks74 with rail and elcan, its real hard to tell cause both guns shoot well....
its really a matter of scenerio and field ull be playing on.