I have kept German Shepherds for over 40 years and when a couple of years ago me and hubby decided to get another one we got in touch with Vigil GSD rescue, boy do we wish we hadn't, every single dog we were told about (because we have experience, my hubby is an ex army dog handler/trainer), every dog was either a bad fighter,aggressive with children, bad with livestock (we live on a farm!!) etc, while we could probably have handled the ones who were fighters there is no way I would take a dog that is likely to attack a child and even fighters you can never let run off lead. believe me you are better not to have so much experience, John Biggs who has the dogs that you've the links to is good though he takes Vigil dogs I believe, so if you decide to go with a GSD make absolutely certain the person you are adopting from understands fully that you must have one that is 'bomb proof', when you have a good one you won't regret it I promise.
Good Luck