Coming from someone whose mother breeds dogs, lived with them their whole life and has trained them (in Schutzhund) for half his life, I will tell you that it is, without question, the owner and not the breed of dog.
Yes, some dogs are bred for certain purposes, but how they are trained (or in most cases, NOT trained) dictates how the dog will behave. Also, not all dogs are good for a the purpose they were bred for. I, personally have had 3 good Schutzhund (personal protection) dogs (German Shepherds, of course
) that made the grade, out of about 6 or 7 that I have tried to train. Some dogs just do not have the drive, or temperament for the job. They are either too aggressive and you cannot control them instantly with a command, they have no drive and do not train well, and some are just crap at tracking and get distracted when trying to follow a scent.
You can tell right away by the neighbor walking his/her dog who is in charge. It could be a doberman or a pug, it doesn't matter one bit. Some people should not own dogs, period. This is especially the case with dogs that are large enough or strong enough to pose a danger to another human. People get them as "pets" and let them do whatever the hell they want. And in most cases, they NEVER listen to the owner.
On the other hand, I have seen some of the dogs I've owned do some amazing things such as: track a person for miles (even across running water), engage and disengage an agressor (the guy with the "sleeve") on command, and even walk across a 2x4 across saw horses like a dang cat.
I have never had a need for a leash on any shepherd that I've owned, EVER, after they have been trained. I tell the dog "Foose" (all commands are in German, of course
) and it will walk one step behind and to the right of me, wherever I go, regardless of distractions. I could also go to the store, tell the dog to sit outside, be in the store for an hour, and come back and the dog wouldn't have moved an inch.
But to sum it up, obedience is mostly about the training and the owner/handler, not the breed of dog.
Don't believe me? Can your dog do this?