Door works great, our two dogs use it, the peanut butter on door suggestion was needed for one dog (the smart one I thought). Installation took some time through the wall but well worth it. Smaller dogs may need a platform entrance in order to be at correct height. One of our dogs is a dachshund who needs a "lift" but he is only 4 months old. He was first to learn to use door after only a few tries. Door costs more than others but have already had a great customer service experience due to one dog chewing up the long range RFID tag which I should have secured better to collar to prevent her from getting it in her mouth. Door is well built and study construction. Note, you have to cut the aluminum wall sections that make up the tunnel through wall. (nice jig saw blade provided). I didn't cut the top section except to round off outside corners, thus creating an overhand over exterior entrance. They sell an overhang seperately, but this worked well.
This is the most complete and state-of-the-art doggy door on the market. It is worth every dollar. Our dogs love it and we no longer have to worry about letting them in-and-out. The only negative would be a dog that brings the outdoors inside. Nothing a little training can't address. We had ours hardwired and we had a need for a ramp to transition to the outdoors.