I've just done a cursory review, but it looks like the new one has a more advanced mechanism for figuring out where to put civs, and what they will do. It also looks like it has set up hit and killed eventhandlers for them but I'm not sure how to tap into them. It also may lead to some eh-confusion, but I don't know.
It also creates a civilian traffic fsm which will likely render obsolete my main claim to ArmA-modding fame. (And that is ok with me - theirs is a much more elegant system.)
Generally, it looks like the civs will seem more "organic" in the cities... less artificial.