Have almost 30 yrs experience in residential construction/remodeling. And TGIF too.
In what context are you asking? My personal preference is natural slate.
Longevity, cooling costs, overall maintenance. I live in the Southeast and metal roofing seems to be the more popular choice in rural areas. Just wondering if metal roofs really do hold up longer and thus are more economical in the long run when compared to asphalt shingles.
A "true" standing seam roof is a good investment but very pricey. A "snap-lock" standing seam roof is a good choice if budget is an issue. An exposed fastener metal roof IMO belongs on a shed or barn, not a home. The "lifetime" warranties on some asphalt shingles aren't worth the paper their written on. I don'r have enough experience with the stone coated steel roof systems (can look like woodshakes or terra cotta tile) to speak on longevity, but they are a giant PITA to install.
Metal roof or shingles?