I used a shock collar on Sierra. I was very apprehensive about it at first, but hubby said it would help because Sierra was SO BAD!!! I tried everything i could think of and notheing worked. Her behavior was just getting worse and worse. So finally I relented, but insisted I feel it before putting it on the dog. I figured if it didn't hurt me it wouldn't hurt her. It didn't hurt it was just an uncomfortable feeling. Kind of like touching your tongue to a 9 volt battery. And it's a momentary feeling, not a continuous shock. Well, it has worked wonders with her behavior. She now understands that when we say no,it means no and she's just all around much more well-behaved. Even commands we didn't use it for, she listens to now, for the most part. It only took a couple of weeks and we rarely use it anymore.
Now although it can be a useful teaching aide, it unfortunately does have the potential to be misused. If that dog was consistantly yelping whenever the button was pressed, then in my opinion, the dog was being abused. We never had it turned up so high that Sierra yelped. Just because the dog is behaving because it is afraid of being shocked, is not "training" your dog. Sierra was given ample chances to obey our commands before we rsorted to pressing that button and it was only used to stop bad behavior such as her eating animal poop she would find outside.
So my opinion is, I'm not entirely against it, but it should be used with care and after everything else had been tried.