We have had the Invisible Fence almost since it came on the market, over 16 years. We have had Sheepdogs, a Golden, Mutts, an Irish Settler, and Bernese. Two were very stubborn, but it worked for them, sometimes using a stronger battery, or longer prongs. I do have to say that the only problem I am aware of is with Radio Fence, which I think you install yourself, and there is no support system. The Invisible Fence brand to us is superior, in that they will come back as often as you need it to get your dog trained properly. And that does not mean repeated shocking. My neighbor had Radio Fence and was so frustrated, she returned it and bought an Invisible Fence and even installed it herself, but the training was what made the difference. They also offer several frequencies so that two systems can work next to each other. Our 14 month berner, was trained at 6 months, and after 2 sessions was completely trained, with or without the collar on, he won't go past the flags. He knows the boundaries and respects them, running, playing, and exploring. In our neighborhood, everyone has the Invisible Fence, there are no dogs running free, but they all communicate with each other! I guess my only concern now is Coyotes, but the dogs are never left out alone. I highly recommend the Invisible Fence brand, Tailwags from Muddy CT Daisy, Chance and Oliver With Caymus and Max always in my heart.