You need to compare retail prices for the true difference of $160:
Vaq $829 - hand fitted blued steel grip frame, wood product grips, and reverse indexing pawl system.
BH $669 - generic fit alum alloy powder coated grip frame, plastice grip, adj sights, and no reverse indexing pawl system.
As far as strength differences, the frame size makes no difference it's the cyl size. The larger frame is only to accommodate the larger cyl. And the 44 Mag Vaq has the same large frame and cyl, same strength. The advantage of the large cyl/frame BH only pertains to the 45 Colt.
So that's the reasons for the prices.
Hope that helps,