Awwwe, poor Puck. That muzzle does make him look kinda Hannibal Lecterish.
I just got a prong collar to use with Keiko. After months of working with her walking, she has plateau'ed out. She needed something to help her get over the last hump so she will be perfect and can take the CGC test. So I am using it for training purposes only, and should only have to use it a week or two.
Previously I have used harnesses, and I do like those as well, as long as they are used properly. I have never really liked Gentle Leaders or Halit's although I know of many who use them and it works for them. Just personal preference.
I was told never to use a prong collar on a type of dog with thin skin such as greyhound as you could cause damage. I was also told not to use one on a dane, and luckily, I never needed anything for Gunther.