Both breeds are great with family,intelligent,very protective,loyal and devoted to its owner.
But Doberman is my choice, doberman's is more of a baby type while rottweiler is the mature type dog. Doberman's is very dependent to its owner so having said that, dobies are more loyal and devoted. Rottweiler can stand alone without its owner(some),they can live with that. and personally doberman is more good looking while at the same time intimidating to the strangers, Doberman's actually outranked the rottweiler for the best guard dog in the world but i have to admit rottweilers is more stronger,more masculine and more intidimating because of its size while dobies is more on Agility..
But Wait, guys did u know?that Rottweilers were part of making the doberman along with the german shepherd,greyhound,great dane,german pinscher.etc? So, rotts and dobies are very related..
to know more about dobies,watch this video:
YouTube - Dogs 101 - Doberman (full)