Where I come from, pit bulls are used mainly to hunt wild boars. If I remember correctly, this is what pit bulls were actually bred for... hunting wild boars.
That being said, I know people who have pit bulls solely for being pets. They tell me how much the pits are big babies who would never bite anyone, but I am terrified of pit bulls. I have known personally three different people who were bit by three completely different pit bulls. One was an adult who used the pit bull to dog fight (he had that one coming).
The other two were small children. In both instances the mama pit bull had puppies and the small kids decided to play with the puppies. Mama didn't like that and bit the kids. It is sad, because the parents just didn't expect the dog to react like that, but pit bulls are different with kids when it comes to their puppies. One of the kids had half her face ripped off and she was just three years old. I myself was attacked by a pit bull, but I was able to avoid being bitten cause I hopped the fence. This pit bull would chase me every day on my way home from school and I would always have to hop a fence or climb a tree... the owner never took me seriously.
All this being said from my personal experience, I think pit bulls are fine as pets so long as the pit bull is sterilized. You should never allow children around a dog who has a litter of puppies, especially if it is a pit bull. I know it may shock you me saying this after what I just said, but I really do feel in most instances it is the owners fault.