"Two medium sized dogs and a cat are thrilled to have this door. With the yard a full flight down from the main living area, we never let them out as often as they move in and out on their own since we added the door. In that respect, we love it, too.
However, inserting the door panel means the main, sliding door isn't locked, and extending the top to hold the pet door in place makes it very difficult to take down and put up. So we decided to put a pole in the track on the opposite side of the sliding door to serve as a lock, but that still meant having to screw the pet door to the sliding door frame, because otherwise it slips when the youngeer dog rampages in or out. Which exposed two flaws: only one edge is drilled to accomodate screws, and it's the wrong edge to use if you want to keep the feature that prevents the pets from using the door from inside the house (we gave it up) and, screwing into a vinyl frame is bad for the integrity of the frame, and an invitation to water damage.
And I'm here today because after 2 years of constant use, the clear vinyl flap has broken completely off.
Still, I've found nothing as sturdy or as ultimately adaptable, and having solved all its pecularities, I'm going to buy a replacement flap or two and happily keep using it."