I absolutely agree with using a prong collar. I also agree that they look awful! But they are not. The idea behind them is that when your puppy pulls ahead, the colar tightens and it is not painful but more like their mama's quick nip on the neck to tell them to stop it.
It is a great training tool. They come in plastic too, for animals who are too timid for the full metal prong collar.
There are other methods too, but I found that using the prong collar works magic for us. We tried changing directions, stopping, Gentle Leaders, treats, commands, but nothing worked until we used the collar to enforce the commands. It works for all types of training.
Our dogs now come right to us when we say, "Let's get dressed!" Which means to put on the prong collar...they come and sit in front of us and wait for the collar to be placed. We still reinforce with praise and treats, but you should never give a command unless you can back it up...the prong collar lets you do that.
There is a special fit to them, so be sure you learn how to properly fit them, they are not worn like choke chains.