Earlier quoted context omitted.
The Amazon guarantee would go a long way with me. Something goes wrong, I don't have to worry about battling it out with the contractor. I call Amazon and let them deal with it. I can't say it's worth double the price until I actually need to use one of their services but I would definitely accept a premium for the hassle free service.
You'd pay double for a guarantee?
Consider we're talking about $150 installation for something in my house, like a TV. That could mean knocking holes in the wall. Searching Yelp reviews and interviewing contractors can be time consuming. Then, if something goes wrong, my wall could be ruined. Taking the contractor to court to recover damages is a massive investment.
That might not be worth the trouble if I could have Amazon send someone and cover all headaches. It becomes dead-simple. "I'll just use Amazon's guy"
There's no question, it's a premium service, but you're getting real peace of mind with it. It's not like you're only paying for a brand name, you're also getting a guarantee from a trusted company.