I see no problems with prong collars when used properly. But with my two dogs it just isn't necessary. Roxy already respects the leash and Hades, well, I don't think that would help his pulling problem at ALL. He has a very high pain tolerance, and would pull regardless of what I put on him.
I guess what we used to teach the heel was the method mentioned before. The "walk the other way tactic" but combined with a leash/verbal correction. Once they caught back up to me, "Oops! What happened Hades?!?! Where were you!!?!?!".
There are so many different ways to teach one thing to a dog.
And which method is "the best" varies from dog to dog.