replacement windows in tucson

We are replacing original single pane aluminum slider windows in Tucson. Have 3 quotes between $14,000-$19,000 for 11 windows and 2 patio doors. Home Depot is carrying a Simonton 6000 series slimline vinyl window. Local company has Amerimax windows that tout their Super Spacer. The high-end local company has Winchester Bristol that is vinyl clad aluminum, and claims everyone else's vinyl windows do not have the reinforcement that would keep them from warping, and their warranties do not address warping. Summer heat is a big issue here!

They also point out that most warranties do not guarantee any particular amount of gas remaining between the windows after they leave the factory.

Any comments on these issues?

Heat of deformation temperature on vinyl is around 160 degrees Fahrenheit. That being said, aluminum and fiberglass windows are much better suited for desert climates.

Thanks. We had not realized the cost would be so high--close to half of what we spent remodeling doing most of the work ourselves. Shopping for windows seems worse than for mattresses! So many claims about so many different aspects. Hard to know what are the gimmicks and what are the true essential things to determine quality. Any guidance will be appreciated.