I used to have one - my cat Boo loved it! The only bad part is the kind I had, you need to drill through the window sill to anchor it (i was renting and I did it anyway). I still have it, but where I live now there aren't any ideal windows to put it up in. I do have one window where it would work, but it would hang over my bed, and it is the side of the house facing the neighbor's and I don't like leaving those drapes open. I suppose the cats could go behind the drapes, but I 'd rather not have the neighbors peeking in my bedroom windows!