I have used the Gentle Leader with Drake for training and it helped control him when he tries to pull. That is when he doesn't feel like pawing it off and we don't actually get to walk. Plus Drake has gotten so big now, that the GL doesn't control his pulling anymore.

We now use a prong collar to train. He no longer pulls when we walk and doesn't need the collar. When we practice obedience training or teach him new commands, we use a prong collar. However, unless you are taught the correct way to use a prong collar, never use it.