You have had a couple of good articles about having dogs for retreat/home protection recently. I couldn't agree more that dogs are a wonderful resource in many ways. I have two German Shepherds who keep my farm and home safe from humans and predators. There are a couple points I would like to add.
First of all, not all dogs will fight to protect their pack. I had a German Shepherd several years ago who would try to hide behind me if there was danger. He was a complete coward, in spite of his attack training. When picking a protective dog, a person should size up the personalities of both parents, if possible. If the parents are rather laid back and unprotective, the puppies will probably grow up with a similar temperament. I have noticed that two dogs seem to be four times as good for protection, but they are also more difficult to control.
And once you have a protective dog, it is important to recognize that the dog doesn't always know when not to bite. A dog bite can be a death sentence without antibiotics, as infection is almost a guarantee. If your dog accidentally perceives someone to be a threat and bites him, there are numerous bad things that can happen to the you, dog, and the victim. My dogs are very protective and aggressive. I have to "protect" them from being in situations where they could get themselves in trouble. Although they are definitely my buddies, I have to handle them more like weapons than pets.
And lastly, dogs are not bullet proof. If there are desperate people who want to raid your retreat, do not believe they will hesitate to shoot your dog. In this situation, the dog will need to be protected too. - Hobby Farmer