Gentle Leader v. Harness
Apologies if you opened this thread thinking it was about Kim Jong-Il. We recently purchased a Gentle Leader leash for Jellypooch and was wondering whether anyone has had any success with it, especially as opposed to a harness-type leash (which we will be purchasing soon if she doesn’t stop rubbing her face in every shrub she passes). We’re basically trying to get her to stop pulling when we walk her, and not jump on people. She’s a 3 year old English (read: smaller) Golden Retriever. How long did it take your dog to get used to it, if s/he did? Any helpful tips? I’m fairly sure we have it installed correctly, although I’ve seen rope tricks that were considerably less complicated than this thing.
All of our Guide Dog puppies use them as part of their training, and we’ve had success. We started much younger than you are, so it might take a while for you. They’re really useful for yanking the dog away from places where she shouldn’t go, and for keeping her head up.
We’ve never used harness - the dogs go into harness as part of their later training.
We don’t use one for our pet dog, and he does sniff everything, but he is quite literate and we wouldn’t want to interfere with his doggie buddy list. 
They’re excellent for training but not good for just yanking. Teaches the dog nothing unaccompanied by verbal commands. I watch the guy across the road yanking his dog around and I bet he wonders why his dog doesn’t learn anything!
Verbal commands are the best way for your dog to act as a companion…gentle leaders are mostly for sniffing dogs, not good for herding dogs.