Before deciding you should really get 3 estimates and compare the contractors. Most people tend to go with the middle estimate unless you gget a bad feel about the company.
We have had three people in, and we never heard back from the independent guys. This is a huge company that has a 5 day start to finish program, a 5 year warranty and all sorts of other pluses. We're not defiantly using them yet, but we are strongly leaning that way.