German lines.
Germans take great pride in this breed; it is a national treasure, and breeding rules in Germany are strict. All breeding stock must pass hip certification, prove sound temperament, earn a working title (Schutzhund/IGP) — a real challenge to achieve — and pass an endurance test of roughly 12 miles. Only the best and healthiest dogs pass their genes on. Within Germany, the breed has split into two types:
Working lines
Bred mainly for working ability. If you want a dog for detection, search and rescue, or serious sport, look here. These dogs can make great family companions too, but some require an experienced handler.
Show lines
Strikingly beautiful, head-turning dogs whose beauty is functional, not abstract. Larger and brighter in color than working lines, with softer, more agreeable temperaments — yet they too must earn a working title and pass courage tests to be bred under SV rules. Exceptional family companions and protectors. They are no couch potatoes: they need exercise, training, and plenty of social interaction.
American bloodlines.
American-line German Shepherds are practically a different breed, as their breeders generally do not follow the international breed standard. These dogs often have thinner bone, narrower heads, exaggerated angulation, and softer ears and pasterns — and several health concerns appear more common among them. Critically, no hip certification or temperament testing is required by the main U.S. registries. If you choose an American-line dog, make sure that not just the parents but at least four generations of ancestors have OFA-certified hips.
Back-yard breeders.
Then there are people with little or no knowledge of the breed who simply breed their pets — no health checks, no evaluation of character or structure, no breeding program. "Not everyone needs a show dog, some people just want a pet" is the common argument. True — but doesn't it make sense to get your pet from proven bloodlines, where generations of ancestors were health tested and temperament checked?
If looks, ancestry, and health testing don't matter to you, consider adopting from a shelter or rescue instead — a noble thing to do that reduces the demand that keeps back-yard breeders in business.