I think it depends on the dog but everyone is right in that you need to know how to fit/use it properly. It was my goal to be able to stay at a flat collar and I have trained accordingly and until Ruger turned into Houdini, I did. He now wears a martingale when we are out and about. He walks wonderfully and I don't need it for pulling or anything but he liked the idea of standing still and then yanking his head out of the collar. Amazingly enough, he didn't go anywhere.......I think he just liked proving he could. After that when he felt like he wanted to be free, he would just houdini himself out. A martingale works well with him because he just needed to know that he couldn't pull out and he is fine now. LOL Just depends on the dog and the bahavior.