She sounds like she has the proper doberman temperment as i have seen described many times, their temperment can be described as stand offish not aggressive. All the other dobes i've met have had this same personality trait. To be honest i wish Ellie had it, i swear she thinks shes a lab. She's so bouncy and will jump all over and lick strangers, would prefer it if she was stand offish as she'd be easier to train!!
