I am sure some of the more experienced members will chime in shortly, but the most important thing IMO other than your previous experience and current lifestyle is what are your plans for this pup. I recently purchased my first WL GSD, and the breeder picked my pup based on my experience and more importantly what I planned to do with the pup. Having goals of obtaining ScH 3 titling (not mine) will require a different drive of pup than the goal of registered therapy dog (mine).
So what is it that you plan to do with your pup?
Rocky - 10 yo GSD
Toto - 10 yo Rat Terrier
Layla Vom True Haus - 12/09/2012