We also had a quote from Window World in St. Louis and all you said is true. They have a lifetime warranty on parts and labor which is good. We would use the mid grade window for our smaller windows and the top grade for our larger windows. The window looks fine as far as thickness, chambers, weather stripping etc. I checked the company out with BB and it was OK--3 complaints will all being resolved. I also checked BB nationwide and all looked good there too. The only thing is they've only been in St. Louis since last April. They contract out their installers, but have had the same guys since the beginning. Our sales guy said he used to install. We are really unsure about using them at this point. I know nothing about other window companies in St.Louis, so don't know who to call next.