Stainless steel will not rust, even in the harshest saltwater conditions. Cast iron connections are purposely heavy… they have to be.
Stainless steel will not crack like cast iron, or PVC. Cast iron and PVC are brittle, especially in cold temperatures making it susceptible to cracking during impacts from lawn or snow removal equipment, vandalism, loading dock equipment, and etcetera.
Impacts may dent stainless steel, but impacts will not crack stainless steel. At the end of the day with Piedmont products, you still have a workable downspout connection not a broken piece of cast iron or PVC that must be replaced.
Although stainless steel is far more expensive than cast iron per pound, it takes far less material to produce Piedmont connections than comparable cast iron connections. Stainless steel is lalso ighter than cast iron, lighter means less expensive to ship both the raw materials and finished products.