My thoughts on eCollars: they have only 2 places in a training program, and only for certain dogs and certain people with the self-control and experience use them properly.
I don't think a dog should ever be corrected and no compulsion used in the primary training phase of training. Too often, the dog makes a legitimate mistake or is simply confused on what the handler is asking for when they are learning something and they get corrected. This makes for a fearful dog too afraid to try new things in case they are corrected. They become more robotic and react to commands instead of thinking their way threw a problem.
When a dog has completely and thoroughly learned a command, i.e. sit or down or whatever, you have done proofing, then in some instances I think there is the potential for an eCollar.
For example, if I wanted my dog to Sitz faster, I would train for that--with a high value treat or toy--and only reward when the dog complies lightening fast. If the dog is distracted, I would do stimulus training where we start from far away from the distraction and reward for attention/compliance then slowly approach until the dog can work through the distraction. For most dogs I believe this is enough. Punishment is the lack reward/play. However, for some dogs, there may be a certain stimulus that not even the most high value reward can compete with. For these dogs I think an eCollar or prong collar correction may be warranted. Only, though, when he dog has been proofed and you know they know what you area asking for and they are simply refusing to comply. I would use sparingly.
The other instance I think an eCollar could have merit is in self-satisifying behaviors. I subscribe to the notion that most GSD have some degree of OCD and that should be focused on us when they are young through tug/treats/etc. so we become their primary source of entertainment. If a dog engages in negative self-satisfying like chasing birds, their tail, or barking at the fence incessantly, I think not only can these behaviors become hard habits to break because they have discovered they are fun/get some form of satisfaction from them, but some of there drive/attention is taken off of you as the 'fun' person. If, using stimulus training an redirection, these behaviors can't be broken relatively quickly, I think an eCollar could be used to nip the problem in the start.
Generally speaking though, I subscribe he marker/reward based training for almost any behavior. Especially for high drive dogs, I think the denial of a reward is a punishment in and of itself. I really like the ideas discussed in Ivan Balabanov's Advanced Schutzhund and the idea of Ultimate Punishment, i.e. reward denial, to make dogs more active thinkers on and off the field. His method involves no use of compulsion even with the most advanced and complicated of training tasks. That said, again, certain behaviors need to have a consequence if they are harmful to the dog or others, but only when he dog already knows what is being ask is just refusing.