I can sort of understand the arguments against buying from people who aren't specialised breeders, but I just wanted to share the story about my dog.
Now, I'll hold my hands up at the start, and say we didn't know enough when we went looking. We suffered the common first-timer problem of thinking we knew more than we did. We both know a hell of a lot more now, and would go about getting our second pup differently.
We'd scheduled a trip out to two places, and the first one was a bit horrific. Hell of a lot of dogs, the pups were a bit old, with no house-training, and the whole setup was very much the BYB I'm imagining from this thread. We weren't impressed. These were essentially a mongrel cross.
The other pups we were looking at were border collies, something that I'd quite liked the idea of. We came out of the first lot, and sat in the car, and decided that we had to be careful looking at the second lot, as they would likely look good compared to the first.
The second lot were produced by a family who owned both the parents, and had an unfortunate accident. They'd owned the dogs for years, and been good about keeping them apart, but failed this time round. They'd produced nine incredibly cute border collie pups, of which only two were left. We fell in love with the bitch of the two, and decided we had to have her. (Note the utter lack of response carefully weighed in my previous paragraph.)
They'd done a good job, and had obviously done their reading, with all the pups cared for. But it would have been reasonable to expect the dog to not be great.
A year and a bit on, that's not true. She's not perfect, usually in response to her recall when there's a more exciting dog about, which she lost when she hit teenage, but we're slowly building back up. But she's a dog that does nicely at the obedience, and the agility and so on, and I would like to think part of that comes from the way she was raised as much as from her parentage.
If tl:dr, then let me say: don't automatically discount family breeders, because they can sometimes have the best of intentions and stay good friends with you afterwards.