I think they can be viewed in different fields. Scattergun specializes in creating tactical (sorry, Kodiac) shotguns. Vang specializes in barrel work that reduces recoil and pattern size.
If I ever get off my dead butt, I intend to provide a preliminary review of the Scattergun 870 which I recieved last week. Noteworthy is the fact that the barrel is going off to Vang as the pattern size is simply unacceptable. Scattergun is not responsible for this...it's luck of the draw with Remington, as I understand it.