Slate can be easily damaged by hail and your kids baseballs. Aluminum will be resistant to all the sizes of hail except biblical sizes. Aluminum also will ref

Slate can be easily damaged by hail and your kids baseballs. Aluminum will be resistant to all the sizes of hail except biblical sizes. Aluminum also will reflect pretty 100 percent of the heat from the sun - allowing you to have an insulated/conditioned attic if you want. As to cost - aluminum shingles are pretty expensive too so probably no cost savings there. The higher quality fiberglass windows have resins and treatments that are pretty much impervious to UV light...so that has been a problem with fiberglass windows but not so much anymore. Another option are steel or aluminum windows. There are some very high quality windows made out of that material as well. I do have links...will post them later.