German Pinschers
So, you are thinking about a German Pinscher?  What are they like?
Well,  it seems to me they definitely have a lot to offer- everyone who gets one seems
to feel they are the perfect dog, and many want another.

                                        So here are some of my thoughts...
German Pinschers are an active breed, not so active as a Border
Collie, but quite active.  I personally would not classify them as a
hyper breed, they are also quite happy to snuggle on the couch.

Their smooth coats are easy to care for- this is something I really
like.  

In general they are hardy and long lived, but they do have some
health concerns, especially if you intend to breed.

One big thing a lot of people ask about is temperament.

German Pinschers were originally bred to guard and hunt vermin.  So they can be quite prey driven at
times, and typically will naturally protect you and your house.  Some German Pinschers do have
temperament problems, this is not correct for the breed.  German Pinschers should be friendly.  
I think one way to help find out about the temperament of a breeders dogs is to ask questions like-
What do they think they should act like, and how many have they had returned or euthanised for bad
temperaments.  If a breeder tells you that you have to raise it very differently from all other dogs, or  
that they should not be good with kids, then keep looking.

With that in mind though- I still don't think it is best choice for a first time dog owner, or family with a
lot of  kids running around, especially unsupervised.

If you take in to consideration all of those thoughts, they are wonderful dogs!

My suggestion is to ask a lot of questions about the parents, and see them if  possible.  

As for with other animals.  I think that their prey drive could be an issue if they were not ever raised
around  cats for example then you added a kitten after the dog is grown- that could be bad- I'd think
even for the nicest German Pinscher.  But I have four cats, and several German Pinschers and they
are all just fine together.  I would not think they would be good with small cage pets- this is what they
were meant to kill!
I will be adding more info about the breed