Things to look for in a 'Responsible' Breeder
This thread is a good read when trying to find a reputable breeder and what things to look for. There are many different "kinds" of GSD's so it depends on what you want. I know you said a companion dog but that doesn't mean you have to "settle" for pet lines. Most litters will have companion pups available so breeding specifically for that quality is pointless. Now, I know nothing about this breeder so my above advice is not directly regarding this breeder. The best thing you can do is visit these breeders and see the dogs they own and represent. As well as their facility. Good luck in your search!