I've known two pit bulls and a Rotweiller. All of them were and are very good dogs, none have ever attacked anyone.
On a list of biters, the German shepard is number one. In the pit bull, there is a latent desire to dominate, but it is not a problem if it realizes who the alpha male and female are in its pack. They are almost impervious to pain, so when they do bite they can do terrible damage. My grandson has a pit bull, its name? Bubba. And, yes the name fits.