I think all the posts on this thread have been great!
I don't know what it is like to raise a puppy because both of my dogs have been rescues, but I have read enough on this forum to know about some of the challenges of raising a puppy. I have also read many posts about the problems new owners of rescues face, but somehow, it seems we deal with those more as individual issues without ever acknowledging that part of it comes with rescuing. In other words, everyone acknowledges how hard it is to deal with a puppy landsharking, and they should because it is a common challenge and it IS hard. But most of the time, we don't necessarily acknowledge the common challenges of bring an 85 pound adult dog into your home. If a puppy is over-tired, cranky, fearful or misbehaving, you can pick it up if need be, like you would a small child in the same circumstances, and put it down for a nap, comfort it or remove it from the venue. The same thing is not always that easy, and may be impossible, if you are bringing a sixteen year old adolescent into your home or an 85 pound adult dog, particularly since many of them carry baggage from past experiences with humans.
My experiences with rescues have been good and I wouldn't trade either one of mine for a minute, but Newlie was a little bit of a challenge at first, mostly because he was much younger than we thought. We were told he was between 3-4 years old, but the vet said "No way," he was more like 1-2 years old. And Newlie was, and is, a sweet dog, but the energy, my gosh! I used to think he had springs in his legs. I can't tell you the number of times, I would be out playing with him in the freezing cold, pitch dark, backyard after work because if I didn't, he wouldn't be able to stand himself.
There are some shepherds who would probably not be a good match for first time dogs owners, but many others who would do fine as long as their expectations are realistic and most importantly, the commitment is there. Life can throw any of us some curve balls, but when I adopt a dog, I take it for life, either mine or theirs.