Window4U is actually a very good contractor by the name of Dave that runs probably the most well respected window replacement company in Chicago. His phone number is on the website as well. I suggested several brands in my previous post. The 4 brands that you have looked at so far are average at best and all high pressure sales organizations. You will get long sales pitches that start with vinyl windows costing over 1K per unit and drop as you haggle. That is an exhausting process and especially if you consider that the 4 windows that they would try to sell you are middle of the pack at exorbitant prices.

katie, that is a VERY open-ended question. The price you can expect to pay can very significantly based on size, option content, installation circumstances, business model of the installation company, etc. We would need significantly more info to comment more specifically on what is or is not a fair price. What I can say, is that for a very broad range of pricing on a good product from a reputable company, you could be in the $400's on the very low end, up to knocking on the door of $1000 if you have a Cadillac option package and complex install. The most highly regarded vinyl lines frequently mentioned are HiMark, Sunrise, Softlite, Okna, Polaris. They all have a "good, better, best" product lineup as well.

1) What do you consider a retail store? My preferred list of vendors would be a window dealer/installation company, followed by lumberyard/building supply house, followed by box stores. You will see a linear decline in quality and performance as you move down that list. 2) All of those items are important (performance, quality, longevity, value), but the good thing is, when you are looking at vinyl windows they generally move the needle in sync with each other. The better the thermal and structural ratings are, the better the quality is and the longer that they will last. U value, air infiltration, and design pressure are the big ones to look at. 3) A few vinyl product choices that are very well made and offer great performance are Okna/Himark, Softlite, Sunrise, and Polaris. I know that you mentioned trying to find a product that might not be as "well-known" among pros, however there is a reason that those products are highly regarded. That said, you should be able to find a good performer that is more "regional" , just use the performance ratings of the better options as a guide for comparison. Alternatively, if your main concern is trying to find a dealer of those products, as someone else suggested you could contact the manufacturer and ask them for a referral in your area.

You are in the window fabrication capital of the US. You have your pick of the litter. Soft-Lite Elements, Sunrise Restoration, Polaris UltraWeld, Kensington Quantum II, etc. All great options and all available where you are.