One of my SAR teammates had that pack for their GSD puppy and it works pretty well for the price and for introducing the dog to backpacks. It doesn't hold up too well if you are into doing heavy duty backpacking and are going to be in backcountry areas in rough terrain, though. Or in harsher weather conditions, etc. But it will do for now. It doesn't have a lot of leeway size wise if your GSD ends up being on the larger end though.
If you are looking for a much higher quality, more professional pack I would recommend the Ruffwear line. We haven't tried their backpacks yet but their Web Master Pro Harness is standard issue for our SAR team. The harnesses still look fairly decent after a year in the brush, thorny bushes, cactus, snow, rain, mud, rivers, dirt, puppy teeth, etc. The quality is definitely there and they are very secure so I would trust that the backpacks are just as high quality and secure on the dog. I am going to eventually purchase the Palisades pack for my GSD for personal backpacking trips as well. They also sell additional accessories such as a Brush Guard, Rain Cover, Collapsible Water Bottles, etc. They are definitely a bit pricey but I feel that they are worth it. The L/XL sizes fit dogs fairly well all the way up past 130lbs.
Kurgo makes some decent packs for a bit lower price but they also can be limited size wise if you end up having a larger sized GSD.
Ranger - 1996 - 2009 RIP
Jackie - 1997 - 2016 RIP
Dante, Kenai (SAR Dog IT), Luna (SAR Dog), Pebbles