When I had my barn built by a company from Michigan, they told me the price for 35 year shingles and trusses on 2 ft was the same as metal. For me, growing up on a dairy farm and seeing all the condensation formed on the inside of the metal roof, it was a no brainer, 35 year shingles.
The cows stayed in the pole barn, it was 3 sided, opened on the south. In the winter all the condensation, mostly produced by the cows, was frozen on the inside of the barn. When the sun came out, it rained.
Check it out and see what the price difference is. I have replace insurance. Get a good hail storm every 12-20 years, so my insurance company replaces my shingles before they go bad.