I bought the same Hasegawa model a few months ago, but I have not had the time to build it. I think the size is OK if you display it hanging on top of a diorama, but if you place it next to the figures and vehicles, it may look a little out of place. Although I have noticed that while the tanks of the AK are getting bigger, the soldiers are getting smaller. I was comparing one of the latest marching AK figures with the Military Police AK, and they are definitely different sacales.
As far as the KC Storch, it will probably be very, very expensive, and even if you can afford it, the few models produced will probably be snatched right away by the hard-core collectors.
Gil