I've been in the Window and Door Industry for most of the last 20 years. I've sold machinery to virtually every company in North America that makes vinyl, aluminum or wood windows. If you use a small company, get referrals - there are a lot of people out there that put windows in that they didnt build and don't know shit about them. They fuck up the install, and the manufacturer wont warranty the product when there's a problem. Some things to look for when selecting your windows are: A welded uPvc frame and sash Insulated (Double Pane) Low E glass Argon filled The "Energy Star" rating is being replaced for building products with new standards, so look for something that meets a "30/30" rating or better (the lower the number the better the rating). The National Fenestration Rating Council website www.nfrc.org has a lot of information regarding energy efficiency as it relates to window and door products. I can't help you much with contractors, but if you have several different manufacturers to pick from on the windows, shoot me a PM and I can tell you who's product is better.