I'm far from an expert, but IME they are no less healthy when they come from a reputable breeder.
They also don't all have the "frog legs." One of my 2 best friends has an ASL male and he's healthy/lacks frog legs. Most of the more well-bred GSD's I met at the shows recently (all American lines) also lacked frog legs. (:
Mom To~ Dakoda (b/t GSD), Acheron (black GSD)