This is where I'm always confused when looking for a pup. Most breeders around here go for "versatility"---in terms of BCs, meaning they are athletically capable of competing in physically demanding sports(agility, flyball, etc) but can also do farm work and compete successfully in conformation shows. If they can compete in the latter, then they have to meet the so-called "breed standard" made by whichever registration is in charge of the competition. This worries me because it's the obsession with meeting this standard that starts the chain of genetic health problems... Of course you want to find a quality BC, but at the very tip-top of the list, above all else, you want a healthy dog. Despite the fact that I love rescues and see the benefit in rescuing a BC in need, the only way to know the dog's exact history is to go through either the breeders mentioned above, a not exactly quality but healthy farm-bred dog, or luck upon a quality farm breeder.
My BC was a rescue, and my BC/heeler came from working stock. But when looking for a quality BC, I'm always at a loss. Of course, as mentioned before, BCs are far less likely to have health issues than say a Bulldog.
In terms of dogs, US seems to have the worst reputation for shoving breeds downhill. (Fellow Americans, don't attack me.) If want the best of quality GSD, America has the worst, while Germany and Czechoslovakia are highest in ranking. If I remember right, the Czechs do not allow any GSD breedings at all unless approved. You can't just go buy two GSDs and decide to have pups. All breedings must be approved, all owners must be approved, and every dog is registered. They thrive to maintain a high quality dog. Their training methods are less than satisfactory, but most of their dogs are excellent. However, GSDs in Czechoslovakia are bred for Schutzhund and police work. Because of their careful breeding maintenance and reputation for remarkable Schutzhund dogs, thousands upon thousands of dogs are imported from the Czechs all over the world for police work and Schutzhund trials.
If you want a quality Rottie, it is most likely not American bred. The best breeders here in the US have imported all of their breeding stock from different countries. GSDs? Breeders who have home-bred, American GSDs are almost unheard of. Even Labs vary drastically. English labs and American labs have quite a few differences, mainly size and temperament.
This is NOT to say that your American-bred dog is a "bad" one. In terms of health and quality, other countries surpass the US quite easily. It's a shame really. I didn't realize the UK was having the same issue with purebreds, but I'm not surprised either.