I own two pb white GSD at the moment, brothers that just turned 1 year last month. One at 128lbs and the other at 109lbs. These guys have an amazing amount of energy for a large dog. Ours came from a police breeder that does whites as a hobby. I would make sure you get some kind of a hip/health grnte if you go to a breeder. I've owned Akitas most of my life but did have one gs/wolf mix that lived to 15. She was almost too smart for her own good. I thought Isis had gotten her brains mainly from the wolf side, but i am seeing how smart these guys are and how many words (not just commands) they have already learned. As others have said just make sure you have the time/space/energy to spend with them, my guys will play frisbee until we both fall over.
Good luck!
woof