There is another discussion about the canny collar going on. We have the GL, GL harness, lupine harness, halti, and now the Canny collar. I like the Canny collar the best, well made. When you get the hang of putting it on it really is I think easier than the GL. You don't have to take it off when you go off lead. Best of all for us, the leash attaches behind the head so Sadie can't bite it. Definitely wish I found this before trying all the others.
I just bought the Canny Collar and could not believe how well it worked with Shep. I have never tried the GL but I would recommend the Canny Collar. It only took about a block before Shep forgot he had it on and started walking. It has made it possible for me to walk him along with our other dog who walks without pulling.