I can tell you there is no way a reputable contractor can offer a high quality window like the Polaris Ultraweld for for a low price. even the most basic install would result in a much higher cost than that. its priced in the mid 500's for regular double pane but triple pane is around 600 from what i have seen and heard. they also now offer heat mirror ,which is expensive but a very nice feature. although that post is well over 5 years old Polaris has made quite a few changes as did most window manufacturers. this window will serve you well for many years; its a high quality product.
Polaris has a few lines so perhaps their original budget line stripped down with no low E or argon iis what the original comments were directed towards. However, they have a newly designed "budget line" (value smart) which is ok and still better than silver line, Excalibur,and MI . years ago they had a very cheap window that they made for rehabs but that window was discontinued.
The ultraweld is a premium window and would not be considered for "rehab work". its meant for homeowners who want maximum energy efficiency and quality. its rated high amongst industry pro's and is comparable to okna, gorell, and soft lite. The Ultra is one of the most solid windows I've seen in a long time along with Okna.
i recently saw their Ultra Patio door at a home show with the "heat mirror feature", real nice and very solid.
Polaris also offers a true stainless steel spacer, not ordinary tin plated. Very well designed window.