I, too, have heard that pit bulls can make wonderful pets. My concern is that no one knows the dog's early history. We had a pit/lab mix that came from an abusive situation. Our adult daughter worked with him and he became our beloved pet at age 2.
He was wonderful until about age 12. One evening, my husband got too close to the dog's face and the result was 29 stitches in my husband's nose. A year later he nipped my elderly mother in the face. That was the final straw and I insisted we put him down.
My point--even if the dog is wonderful now, there is a need to be vigilant. I would never let the dog alone with kids. I would teach the kids how to behave responsibily around the dog. And at the first sign of a problem, there is no choice when it comes to the safey of children. As one becomes more and more attached to a pet, it can be hard to be objective which creates an opportunity for something terrible happens.