I grew up with mastiffs and my parents are on their third, which they purchased from Thunderheart five years ago. They are NOT backyard breeders and are far from a puppy mill. My parents' dog is healthy and has the best temperament of any of our previous dogs. She is an English mastiff and, yes, the masos are "mutts" but tend to be healthier in the long run because they are a new "breed." That's how all breeds start - by making mutts. I have a Cane Corso mastiff that I rescued from the SPCA for that reason - the Cane Corso is a newer breed and is healthier because the lines have less inbreeding. Also, my parents' Thunderheart mastiff DOES NOT SLOBBER except when she is drinking water. We have had other mastiffs that just sit and drool and this one does not. I would whole-heartedly recommend Thunderheart and urge people not to make assumptions based soley on a website when you have never been to the farm or met the owners. These are remarkable dogs and, in my opinion, the best tempered mastiffs in the area.