My wife and I are on our 3rd rottweiler; we have several friends with rotts and know some great rott breeders. All we can say is that they are one of the nicest, warmest, safest, loveliest, faithful, most protective, best-charactered dogs around.
The stereotype of a dangerous breed is just that; a stereotype. Dangerous dogs are dangerous due to careless / stupid / irresposible / bad owners. Upbringing makes a dog. Period. Obviously a powerful dog like a rott will be much more dangerous if unbalanced (i.e. bad upgringing) than a less powerful dog.
Just like a reckless driver on a humvee is bound to pose a bigger threat to the environment around him than the same reckless driver on a mini !!!!