My cat loves it!
I recommend this door.
I paid a professional installer to put the cat door in, so I can't judge how easy the installation is into a wooden kitchen door like mine. The installer had me put the cat's head through the door twice. and it picked up my cat's chip immediately (she was chipped two months ago, so the chip is new). My cat figured out how to go out the door about 1 minute after installation.
Learning how to come back in was harder, as my cat tried to pry it open with her paws and didn't figure out for a while that she had to wait for the click to let her back in (it doesn't click when she goes out) and that she had to go in head-, and not paws-, first.
So I had to go outside and pick her up a few times and push her head through it, and she then learned how to get back inside. It did take a few more tries before I was satisfied that she knew how to open it from outside, and she now proudly goes in and out on her own.
She's a small cat and the size is appropriate for her, as I don't think she would have coped with squeezing through the standard-sized flaps, which are much smaller.
I bought this door because it has a 'curfew' timer mode, so that my cat can only go out during the times I program (which are daylight hours). It will let her back in after the curfew time, but she is very unhappy that it currently clicks shut at 5pm every night to prevent her going out, and I find her regularly sitting by it during the night trying to will it to open! So I usually push a box against the cat door when it's programmed to be shut so that she gives up trying to pry it open. But she also doesn't understand that the microchip door keeps the local bully cat out, so my cat often sits inside our back door guarding her flap from invaders (the box against the cat door helps allay her fears at night).