Aluminum and steel are the two metals homeowners are actually choosing between in Florida, and the deciding factor is almost always distance to salt water.
Aluminum does not rust. In coastal and barrier-island applications that single property outweighs most other considerations. It is softer than steel, so it dents more easily from hail and debris, and it typically costs more per square.
Galvanized and Galvalume steel is stronger and generally less expensive, but its corrosion resistance depends entirely on its coating. Once that coating is breached at a cut edge, a scratch or a fastener penetration, salt air attacks the substrate.
Near salt water, aluminum is the safer long-term choice. Inland, steel usually delivers better value. Either way, fastener metallurgy matters as much as the panel — mismatched fasteners fail long before the panel does.
O'Brien Contracting — Florida roofing contractor, license CCC1335947. Call (239) 919-4485.