I have a miniature American Eskimo dog who hadn't been socialized well as a puppy and tended to be aggressive around strangers and other animals because of her own fear. We've worked hard to rehabilitate her and she's come a long way, but is so anxious that she still barks like crazy when a stranger appears, the kids downstairs are playing outside, the dogs next door bark, or when the doorbell rings (even on TV!). Once she goes into that "red zone," her eyes glaze over and it takes 20 minutes to calm her down. We bought this remote trainer in the hopes that it would stop the anxious barking.
Oh. My. Gosh. Her reaction was almost immediate! The next time she started barking, I hit the button once and she perked her ears up, stopped barking, and ran to me. I was shocked. We tested it again by ringing the doorbell, and this time it was one little yip, then she went and laid on her bed. (Wha?!?) It was amazing. I guess the noise distracts her enough to pull her out of that anxious mode and reroutes her brain so she doesn't work herself up. It even seems to work on the agression. When she growled at my husband because he sat on the couch next to me, I hit the button, she shook her head, then ran up and licked him. Wow! It's like a magic remote control, and we rarely even have to use it anymore. She's learned quickly what behavior we want, without yelling at her. Now we're focusing on curbing the aggression towards other dogs, and getting her to come when called, though I haven't had to use the remote yet. It's definitely progress! She's become visibly more loving and happy now that her mind doesn't put itself into that anxious cycle too often.
Now, that being said, I think this will only work for SOME dogs. My mom tried it on her Golden Retrievers and they just kept barking, ignoring the sound completely. I think it will work best for dogs who are especially sensitive to sounds, and from what I've heard, smaller dogs seem to be more of this type. So I'd suggest borrowing a friend's or getting the $10 "Bark-Off" at Bed, Bath and Beyond first to test out the idea of sound training. If your dog responds to it, then spring for this remote. I'd say it's definitely a great tool if your dog responds to sound!