I would go for the Boxer especial with a small child in the house. Boxers are great with children and the whole family and that's genetically always maintained in the lines of Boxers. Great for families but reserved towards strangers.
Dobermans have a shorter history and gene pool of being a family dog, they were not so long ago mostly used for police work and other security work so breeding was focused on those qualities. Changed recently but not long enough to match the Boxer in his loyalty and kindness towards the family.
Acira