Well, I've bought them ready for a long trip south. I bought them partly because of the second, silvered layer, that might reflect some heat. And partly because of the sensible price.
All I can say for now is that they fit and the quality seems fine. As some reviewers say, the clips don't fix to the screen securely, so can fall off as you are fitting it. I find it easiest to fit one or two to one side, put up the screen, and then fit the rest of the clips. Once up, they stay put. I'll try to remember to post my experience in a hot climate when back in a month or so.