I have a couple different breeds of personal dogs. Besides being a farmer, I am also a full time dog trainer with the emphasis on stock and herding. My working dogs fall into two catagories, herding and protection. I have Border Collies for herding my livestock and my Pyr X Anatolian X Kommodor for protection.
I explain to folks all the time that if you want the job done right you choose the right tool for the job. With dogs there are two criteria, genetics and environment. You need the right genetics, not just the breed, and the dog needs to be raised properly. I always recommend that you get a dog from someone who uses them for what you want, and then get proper advice on how to raise and keep them.
In our part of the world, often as not the LGDs are a mix of guardian breeds that work for a particular place. Three of my guys are fourth generation LGD, the farm I got them from has been using them for a long time. I would never trust a dog to live with my livestock that wasn't bred to live with livestock. Remember that dogs are predators and livestock are ultimately prey. The pups have to be raised with the livestock to consider them their pack. There is more to it but you can get the idea.
I couldn't take care of the farm without my BCs either, but would never trust them to be with the stock unattended. I'm sorry to go on, but I spend a lot of time helping people fix problems that are easily avoided.
Joy