The info on structure (angulation) seems really confusing. Do working lines have better structure?
Don't worry too much about the "angulation" stuff--as long as extremes are avoided, I think it's mostly a cosmetic issue. Angulation is fashionable in show lines, both American and, to a lesser extent, German. Moderate angulation is what you normally see in working lines. Barring extremes, I don't think angulation makes much difference unless you intend to show in conformation events.
In my opinion, working lines have better *working* structure... but show line folks will say the same thing about their dogs! My position is, form should follow function. Whichever structure *works* better, is hardier, with the fewest injuries, and sounder into old age, is the better structure. Of the elderly GSDs I've known, the oldest and healthiest have been working line dogs.
But I have to be clear, dogs with "working" structure do not usually win conformation shows, or get the highest show ratings, so apparently there are many, many knowledgable people, including breeders and judges, who disagree with me!
Oh, and I expect those of you with elderly show line dogs to tell me how great your dogs are doing, and post pictures of them.