What model of each? Most manufacturers have a good, better, best format.

In this case, the the best Plygem is probably better than the worst Milgard.

From a product support standpoint, you can beat Milgard while in Washington state.

I believe I can choose to upgrade to best vinyl of the Plygem and the Milgard. Since we are going with all white vinyl we are willing to pay for the best we can get. Our builder is really pushing us toward Milgard. It is possible we could drive to Spokane to get other brands that may be better than the choices here in town. If you have recommendations I would love to know what you think.
Thanks so much for your reply!

I think the Plygem premium is decent and probably on the level with Milgard's best offering.

HomeSealed knows their offerings better than I do.

I will defer to his opinion on Plygem's stuff.

Unfortunately my knowledge of the product offered by Plygem on the west coast is only second hand, and that is that it is not much better than average. That said, it is probably in the same ballpark as the Milgard. I'd recommend a comparison of the thermal and structural ratings of each to determine which will serve you better. Those two along with Simonton are about as good as you'll find (in vinyl) in your neck of the woods unless there are some great local manufacturers that I'm unaware of.