I have a staffie, and have had him since before we had kids. In the past I have trusted him 100% with the kids because we have had him since he was a tiny puppy and know he has not been raised to be aggressive. However recently his personality has changed somewhat (we think it might be early signs of dementia) and as a result we watch him more closely and don't let the kids play rough with him or be alone with him. He has never shown signs of aggression but a personality change is a warning and we have taken it as such.

I think if you are a responsible owner then a pit pull will be a wonderful pet. Personally if we didn't have a staffie already I would want a pit bull, they are such loyal and affectionate dogs. It sounds like you are switched on enough to know what is safe with your own child in which case your pit bull will only enhance your family.