As far as shiny aluminum goes, it's my experience that it does not remain shiny for long. A coating that kept it shiny would increase cost as well as the proces

As far as shiny aluminum goes, it's my experience that it does not remain shiny for long. A coating that kept it shiny would increase cost as well as the process of making it mirror finished in the first place. Once the coating failed there would be no practical way to re-polish and recoat to anywhere near factory quality and there goes your efficiency. In Florida a dull aluminum surface will be much hotter than a white painted one. Metal roofs are not as popular as they should be because the capitol cost is more and they are often considered low class. These days there are several fancy metal roofing systems that are more popular than 5 V crimp and the classic corrugated. I personally like the classic standing seam style which I saw a lot of in Maine and New Hampshire and are installed by skilled craftspeople. Asphalt shingles are made from the cheap and plentiful byproducts of the oil refining process and crushed rock. They are made from dirt and installed by low skilled labor.