I have two purebred pets, one dog, one cat.
I intended the dog to be a competitive show dog. However, he decided to come across a delicious cat toy and swallow it whole, getting his digestive system in a bundle for a whole month during his major growth period. He's now a little bit of a runt (20.5" and 66lbs is very small, even for a moderate Kotzebue Malamute like he is), but more 'importantly' he sucked up one of his testicles in the whole ordeal and I didn't want to get it "tacked" as I thought it would be immoral. He's neutered and a wonderful pet. I'm almost glad he didn't get the chance to make it big in the show ring -- less strain on my pocketbook and more time to devote to schoolwork.
The cat was my dad's choice. She's an Ocicat from one of the most reputable Ocicat breeders in the country. She was never intended to be anything but a pet. I wasn't wholeheartedly behind this decision until I met the cat -- as opposed to our previous kittens, she was used to people from the moment we got her, very personable, and well behaved (for a kitten). Though I love my two rescue kitties, one of them is horridly aloof and the other is just plain aggressive to strangers (she was a feral kitten and she's very bonded to her two people and her two dogs). It's night and day having a purebred cat and a rescue cat. I enjoy both in their own rights.
Am I going to get purebred dogs in the future? Yes. For sport, mostly -- to compete in conformation and obedience and also to pursue a breeding program in the far future. Would I get a purebred dog with ONLY the intention of it being a pet? No, but I never really intend any dog to be *just* a pet. Will I still have rescues? Yes.
... I'm sorry that didn't really answer your question. WELL bred dogs are usually healthier (because of health testing their responsible breeders presumably did before breeding their parents, they're usually free of genetic diseases). WELL bred dogs are usually a little more trainable, simply because they've been conditioned from a puppy by their responsible breeder to be good dogs. They're not robots, especially if you end up with a nordic breed, but they do show a marked difference from dogs who have been just raised by their mom. The "pure" breeding isn't what makes them this way, it's the responsibility of their breeders that does.
I got a Malamute because I wanted a Malamute. I can't go to an animal shelter and pick out a Joe Schmo mutt there and know what sort of general temperment and personality its going to have (we're talking Big Brown Dog syndrome, rather than something that resembles one breed closely). That's what I like about purebred dogs. Am I still going to have a Big Brown Dog somewhere down the line? You bet. Both the purebred dog and the mixed breed dog have their pros and cons.
