We used this company through our builder and added many upgrades. The most expensive was the added $3000 for upgrading to the 9-light windows in our great room. Beautiful outcome... But it's a lot of window to cover! We also upgraded to the Eco-r5 windows which add an extra layer of coating (r1 value).... Honestly don't know how much it helped, but I hope it does. They were already low-E. if it wasn't so expensive we would have gone to triple pane windows instead, but would have to upgrade to alluminum frame too, which was way out of our budget.
Otherwise, the windows are beautiful but expensive.