Denver window replacement - Vista panorama?

[denvertrout]

I could use some help here. Looking to replace 6 windows in my house and depending on price all the rest (25) and have now had 4 quotes from 4 different companies for the 6 windows in the upper floor. Prices have ranged from over $4000 champion windows to just over $2000 for Vista panorama windows. Two separate quotes for Alside excalibur, one coming in at $3500 and the other for $2500. All the windows qualify for the tax rebate.
The Vista is made in conjunction with Simonton windows and seemed like a good window and obviously a good price.

Looking for information on the vista windows. Specifically air infiltration and then also general advice and suggestions.