+1 on the Okna, easily the class of that bunch and one of the top choices made. I'm not sure where Bourbannais is, but if it is in the northern part of IL you would be well served by contacting Windows4U, a long time board pro. Great guy and he is very reasonably priced on that model... The above recommendation for the 500 series is very good as well if you are looking at a non-woodgrain color.
Bourbonnais is 16 miles from my office and is my home town though I don't live there now. My partner lives there, out by Bon Vivant.
I heard Okna only gave the new dealer the 800 & 400 series so they don't have access to the 500.