Do custom-fit windshield sun shades actually work better than universal ones?

According to reviewers across Amazon listings and specialist subreddits like r/BuyItForLife, custom-fit shades (Covercraft-style and Pigenius accordion designs) seal edge-to-edge with no light gaps and stay rigid without needing sun visors to hold them up. Universal foldable shades like EcoNour and Magnelex are far cheaper and still drop cabin temps meaningfully, but verified-purchase reviewers consistently note small gaps at the A-pillars and the need to wedge them behind the visors.