I'm curious...for this job...
Did you obtain multiple bids for this project?
Did you choose the cheapest installer?
If yes to above, was the contractor significantly cheaper than the other bids?
Did you get a price per square foot for the install?
Did you find out how long this contractor has been performing this type of work?
Did you visit any of the contractors previous jobs?
Did you speak with any of the contractors previous customers?
Did the contractor provide you with a warranty?