I have had my metal roof for about 20 years. It is great but the cost was only 400 dollars more than a shingle roof at that time.
It does get hot in the attic in the summer but the plus is the attic cools 3x faster at night in the summer. This allows the house to cool faster at night.
Yes it does get dented during a hail storm, but being in Texas, august sun pulls the dents out in no time. I just call the insurance adjuster and they right a check for replacing the metal and I wait for august to come. Last time the check was for 2600 dollars, it paid for 2 new work/reloading/gun buildings and 4 rifles
. Sometimes I can't wait for the hail but then.......
Another plus is when it sleets or rains hard it sounds like bacon frying.