I have 2 dogs and it works on one but not the other. My bulldog is great with it. He never pulls and when I don't use it he isn't as good. But my American bulldog is another story. He just does whatever he wants with it on and it ended up making sores on his neck. So I just went with a regular choke chain and he only pulls for a little while because he is so excited. And I don't think it works well for long haired dogs because it won't get through the hair.
Over all it depends on how stuborn the dog is. But I have seen alot of people use this colar with success.

Pros: easily grows with the dog

Cons: not all dogs will learn