I replaced a patio door and three windows with Sid Lipson. I was happy with his service and most of all his prices. They were about 30% lower mainly due to his lack of a web presence and a store front. If you are comfortable working from pamphlets you will get an outstanding price.
The installer was a litle rushed to complete his work. He removed alarms and window coverings and did not put them back on. That was annoying.