Regardless of what you ultimately want in your GSD choose the breeder with care. Health & temperament problems abound in the breed regardless of size, color, coat or titles.
I prefer them oversized but that's strictly personal preference. As much as I like 'em big (leggy & lean, too) size is much less important than health, longevity, structural integrity, temperament, intelligence, discernment & genetic obedience.
My Sam lived 13+ yrs. She was healthy & active until the last months of her life. Djibouti has never been sick, not even mildly, not even when he consumed in excess of 10 lbs of high quality, high protein kibble. Phoenix, too, is sound, healthy, active & has never been sick or needed vet care beyond spay surgery & immunizations.
Whatever you decide on, wherever you go, choose a breeder who consistently produces sound, healthy, long lived uber reliable dogs with intelligence, judgment & exemplary temperaments. Even that doesn't guarantee that your dog will be healthy, but it stacks the deck heavily in your favor.