While I own / breed Dobermans, I train with a GSD breeder / owner / trainer. Consequently, there are a lot of GSDs in her classes as they are often her puppies and their owners.
It *seems* that you can drill a GSD for a lot longer than a Doberman. The GSDs don't seem to mind doing the same exercise over and over, while the Doberman is like I did it 3 times, I got it right, let's move on. The Doberman gets bored. The Doberman is a thinking breed, often described as not blindly obedient. They say that it is one of the reasons that police forces don't use them much these days - that the Doberman is not going to run into a burning building because you tell it to, it's going to stop and think h'mmm, that doesn't seem safe, how else can I accomplish this task? While other breeds will do as told because they were told. I see the GSDs in class to be like that - they do what they are asked, while the Doberman tries to put a new spin on exercises. I just don't see the sense of humour (usually) in the GSDs that I see often that I do in Dobermans. They make fun of my Dobermans and their "prissiness", the way they don't really want to lie down on the cold mats or in the dewy grass while the GSDs just plop down as told.
I'm not saying the Dobe is better than the GSD (they are for me, but not for everyone). I'm just commenting on some of what I see.