After nearly a year in service, 2-thumbs up and nothing I would suggest they do differently. A great product that is both durable and sharp looking.
Measure carefully (they are all custom cut), clean the hatch, and install on a warmish day.
Press the buttons on firmly.
This one is located near the base of the mast, and thus, I've stepped on it many times.
Kind of pricey, but they do a nice job of keeping the sun out (the cabin is significantly cooler and the AC works less) and they can be left in place sailing. Although I would try not to step on hatches on principle, this hatch is at the mast, I stand near there every time I hoist or reef. As a result, they've been stepped on roughly a good many times in rough weather. Not at all slippery and evidently durable. One owner (Boat Galley.com) reported dropping a wrench from the masthead, saving the lens from a certain crack. The only evidence was a tiny dent.
After 5 years on the PDQ, I liked them so much (they are still like new), I added one to my F-24. The forward hatch gets stepped on a good bit and the cover offer some insulation, keeping the cabin warmer in the winter and much cooler in the summer. The the hatch lens will last longer (no UV), making it worthwhile for that reason alone.