The door is very sturdy and still works like the first day after 6 months. The locking mechanism is relatively easy, it has 4 positions: locked, only entry, only exit, open. It makes a little noise when the cats use it, but it serves me well because I can tell when they come in and out.
The installation is a bit difficult, especially if the door has a lining, so it requires a lot of attention when cutting. Also, the screws included are longer than necessary in my case, but it's not difficult to find ones of the same diameter that are a little shorter.