Just my two cents, as I use to deal with Maax (vita) and currently deal with Caldera. Warranty and customer service are infinitely better on the Caldera side, that's just from the support side.
The warranty themselves are actually pretty similar, as Vita has some things at 3 years, some at 1, where Caldera is all-around 2.
My vote, especially if you are in the colder weather, is Caldera since it is insulated much better than the Vita, and it's less!