Stamoid will not breathe, Sunbrella will. That is a real difference. I like Sunbrella and when the waterproofing wears out, and it will, then you just retreat it. If you let water pool on Sunbrella it will eventually start to drip through. But if you have water pooling on your top, it is a poorly designed top. I have a friend that has a leaking windshield and we don’t see a way to remove it to rebed it without removing the flybridge, so I advised him to get a windshield bra made out of Stamoid because it is truly waterproof and will stop the windshield from leaking. He never uses the windshield to see out of anyway since he does not have a lower helm. If I lived in a damp environment I think that I would want Sunbrella in order to let the moisture out. Unless you are going with white, then go Stamoid since white Sunbrella is very difficult to keep clean due to the woven material.