If we would own one it would not be as a pet. We want to eventually get property with goats, possibly a few cattle, and poultry and I keep reading about people using them as predator control buy realized I don't know a thing about them. I do know people who have Great Pyrenees but they keep them as pets.
I think which breed you would want to go with depends on what kind of predators you have around. Great Pyrs are really common here - I don't think I've ever seen any other type of LGD around. And because I'm assuming they are so common, I haven't met many I like.
I do know that there is a Spanish Mastiff breeder in WI whose dogs are with her goats. I drool over her dogs and I want one
so bad. Alas, renting with a LGD may not be the best idea, not to mention the boyfriend is allergic to dog drool and isn't fond of huge dogs. Bah. So I'll have to put my Spanish Mastiff want on hold until we have a house with property.
If you want more info on Spanish Mastiffs, here is a link you can check out:
http://www.fallcreekfarm.net/temperament.htm (<- This is also the breeder in WI whom I drool over. ^^) If you like the sound of the temperament, but would prefer a long-haired dog, Pyrenean Mastiffs are very similar.
When I was looking at the various LGD breeds, these were my favorite. But, I was also looking at them from a pet perspective and not a strictly working perspective. But, what I liked about them is that they are serious enough to do their job, but friendly enough that being on a small, family hobby farm is perfect for them. They'll keep the stock safe, and still be a good family pet. And they are reputed to be AMAZING with children.
If the only predator you'll be worrying about are coyotes and feral/stray dogs, then I think any "generic" LGD will do. But, if you are worried about large predators (bears, wolves, mountain lions, etc.) then you'll need a more serious dog that can handle those predators (the more "intense" LGD breeds).
If I'm allowed to post it (I think I am...), this is another breeder I'd look in to. They have a wide variety of breeds and cross breeds (including Spanish Mastiffs, which is why I discovered them in the first place) that are bred to work and do their job. I don't know anything about them other than what is on their site, but I like what I've seen:
http://www.lgdnevada.com/Home_Page.php