I recently got a dog from a rescue ansd due to small kids being around regularly we were not aloud any kind of terrier breeds because of there nipping tendencies.
The dog we ended up getting is a rottie crossed with alsation all be it they told me he was a year and he was actually 7months and wired to the actual moon they were honest about everything else though.
Dobermans if im not mistaken will only ever have one master at a time so you will be the only one he listens too. I could be mistaken though.
Haha, I have a doberman, he will never be as attentive to me as he is to Britney, but he does still listen and is very friendly to "all members of his family." They are the best dogs ever!! But I tend to be a bit biased.