The difference is how each type of steel resists corrosion and how the surface looks. Stainless steel gains its corrosion resistance from its alloy composition, while galvanised steel has a protective zinc coating. The right choice depends on the environment, appearance and upkeep required. Both can be used outdoors where appropriate.
Stainless steel has a metallic finish that can be brushed or polished, with good corrosion resistance. Galvanised steel has a grey, more industrial appearance. Its zinc coating provides protection, including some protection around minor scratches, but the coating must be maintained. Both materials need cleaning in exposed conditions, and neither is ideal for every setting.
