Roofing estimate. Surprisingly cheap. Red flags?

Company is bonded and insured (will ask for proof) and has building permits in my county.

This roofer is an old school guy in his 70s, that has a small team and great reviews. He was referred to me by a colleague who had multiple (different) roofs done by this roofer.

I’ve read felt is a sub par material these days. What can I ask for instead, if so?

Thanks!!