Gonzo is from rescue, and he would be INVALUABLE to any rancher... he would be the perfect stock/family/guard dog in one, and would work every single day if he was given the opportunity. Our herding trainer flat out told me that he needs a more experienced handler because he's miles ahead of me and my understanding of stockwork.
I think it's very, very unfair to discount the abilities of all rescue dogs. Fozzie might not be the quintessential working dog, but he's incredibly bright, kicks all of the Border Collie and German Shepherd bootays in Obedience & Rallyo, and he's the perfect therapy dog. I adopted him as a puppy, and he has grown up to be trustworthy with any person or animal, in any situation. It's all about being very careful, doing your research, and adopting from a caring/ethical rescue group. Fozzie was raised by wonderful foster parents and his Mom was a very friendly dog; I was willing to take the chance because he needed a good home, he was a very outgoing and confident puppy, and I was positive that I could properly socialize and raise him into a stable adult dog.
I have nothing against buying purebred dogs... I wanted to buy a puppy from a reputable breeder, but ended up rescuing both times. :/ It's not guilt that has made me do it. I honestly feel that it's fate. Both times I just happened to stumble upon each of my dogs and they fit me perfectly! They both do dog sports and have stable temperaments. I do want a purebred dog that I can show/work/and possibly breed someday, but my rescue dogs are not worth any less, and my dogs will always be companions first and foremost.