Installation And Weatherproofing Matter As Much As The Material
Even the better material can disappoint if the installation is sloppy. A well-set fiberglass door with poor flashing or weak sealant will still leak air and water, and a properly installed steel door can outperform a premium slab that was hung door replacement Tysons VA badly.
The door opening works as one system. The slab, the frame, and the sealing details all have to cooperate for the result to hold up through the seasons.
Good weatherproofing also helps either material last longer. Proper drip protection, sealed trim joints, and a clean finish around the threshold can extend service life and reduce the kind of maintenance that gets ignored until a leak appears.
The decision is rarely about one material being universally better. It is about which trade-offs fit the house, the exposure, and the homeowner's expectations.