This is a discussion that can go on and on and on.
I personally, think ANY dog can be vicious. In my lifetime I have come across more mean smaller dogs than bigger dogs. Of course no one thinks twice about them though, because they really can't do any damage. It's like getting hit by a small cavalier or a hummer...what's going to do more damage?
Pitbulls have gotten a bad rap, but not all are bad. Just like I learned not all small dogs are mean little ankle biters, I wish more people would realize that not every pitbull is going to maul a person if they get a chance. I really do feel bad for this breed
I think it all depends on the lines that the dogs come from. I don't think it's fair to hate a whole breed and want to ban it because of some who got breed when they shouldn't have been, and ended up in the hands of the wrong owners.