how to tell a good company from a bad one in just a few minutes..

Yeah, I was going to add that often other younger drivers have ruined it for us. However I would guess that has more to do with experience. I don't see why a 50 year old with 2 years exp, would perform any better than a 25 year old with the same experience.
Problem is, most young drivers are new, and a lot of older drivers are vets. Also there are cases for the positive variables on older and younger, so I think it's a wash. Younger people have less need of off time,are generally more open to learning, and can adapt to, and utilize technology better. Whereas older drivers are generally more reliable due to increased responsibilities, are more independent, and more attuned to small details.