Although I have owned many breeds of dogs throughout my life, border collies, labs, mutts, german shepherd crosses, the pure bred GSD has always been my dog of choice.
GDS are NOT for everyone. A GSD will take over your life and run YOU, if not properly trained from the get go. Boundries must be set for everything and everyone immediatly or you will be in for a lot of unwanted behaviors. Once training has been established, you end up with the most wonderful, loyal, friend and companion you can possibly want. GSD do train easily, and very quickly as long as the trainer knows exactly what he/she is doing. There is no margin for error, or a GSD will take serious advantage.
I don't believe a GSD is too hyper. Hyper would not be the word I would choose exactly. That is just in the training, or non-training. But a GSD does want a job, something to do besides laying around. For us, it was search and rescue with a little bit of tracking and a whole lot of ball throwing. To ask a GSD to lay around and do nothing, is not in their makeup. They are a using dog. They thrive on having a job, no matter what job it is.
They long to be used for anything you would like them to.
As for vocal, yes, I'd say they love to "talk" by way of "moaning" they seem to just be carrying on a conversation like that. It's very comical and I spent many days talking to TRacey and she would answer me back via her moaning sounds. It's communication. Bark, of course. Howl, or sing, sure! If I sing or play the piano, I would soon have a duet going.
A GSD is sensitive and compassionate to your feelings. Just ask me. When I cried, Tracey would automatically comfort me by laying as much as her body as she could across me. One day, I was crying uncontrollably, and she went into Michael's room and brough me his blanket. How did she know? Because she was a GSD totally and completely devoted and in tune to ME.
A GSD will protect you and lay down their life for you. Tracey and my other GSD's would never get aggressive towards anyone without a very good reason, such as anyone suspicious approaching the property or my body. A GSD will get inbetween you and them, probably issues a warning by snarling, until instructed by you, that "it's ok"
There is much difference between the European and American breds. If you do a search on American VS Germans, you will find that these breeders for the most part, hate eachother, and stand by their die-hard particular bloodlines. It's all a matter of perference. It is said that European breds are much better suited for schutzhund work (attack, protection, gaming) than the American because they are more "on the alert" and tougher and braver. They are said to have great protection drive.
Another difference is the size and conformation. A European bred is smaller, more compact in length, and shorter, and may be less angular and have larger bones. They can be more "coarse" in looks.
Americian breds have been bred "for beauty" mostly, dog shows. They are overall bigger, taller, longer, and can be more angulated in the hindquarters. However, the angle in the hindquarters itself is not a predisposition for problems such as hip-dysplasia and relating back problems. An American bred as well as it's European counterpart, both can have those problems if they are not bred for proper conformation, in which the hipball will fit properly in the socket. The angle itself is not the problem. It is said that American breds are not as aggressive for shutzhund type work and are more suited to being a personal companion. Police, the Army, usually will select a german bred for war or work because some of them are bred not to feel as much pain as their American counterparts.
This all being said, some breeders will combine a European with an American on occasion. Politics.
I don't necessarily agree with everything that I have stated. Those are just the basics that have been established. It's personal preference in which kind of German Shepherd appeals to you. I have found that the American German Shepherd is every bit trainable for shutzhund activites as the European counterpart. Tracey was my first American bred and although she had great "ball drive" she was incredible with tracking and her search and rescue training.
Both American and European lines have very much to offer.
In short, a German Shepherd dog properly bred and trained will be hopelessly devoted to you.