I have had the Premier Gentle Leader Headcollar for about a year now. We have a somewhat rambunctious Bearded Collie (which is to say, a typical Bearded Collie). And whenever we walked him he would go somewhat bananas pulling at the leash or jumping off in random directions no matter what we tried: treats, collars, harnesses, even that “CHHHHT!” noise that Cesar Millan recommends. Nothing kept him consistently manageable.
The Gentle Leader, on the other hand, just works. It is some sort of black magic from the Animal Gods.
Actually, it’s not; it works based on how it’s put together and how it attaches which is in such a way that if the dog pulls or jumps, his nose is GENTLY tugged downward. It turns out dogs do not like this, so they quickly learn to avoid it by walking at your pace calmly.
I went from a leash that was as tight as piano wire on most walks, requiring a lot of upper body strength to keep our 45lb Beardie in check, to a pretty much completely slack leash — allowing a much more leisurely, less tiring, and more enjoyable walk.