My uncle had one.
These are great dogs, very smart and well tempered. they are exceptionally well with kids, they are actually called the nanny dogs because they are so good with children.
They're not exceptionally well with other dogs, unless raised around them from a young age, exspecially other dogs of the same sex.
Theyre also very protective of their family.
My uncle had to get rid of his dog because the neighbors pit bull jumped the fence and got in a fight with it and since then all it wanted to do was fight with other dogs. before that it was real friendly with other dogs. guess he found out how much fun it was to kick a pit bulls butt.
Theyre awesome dogs though and I would love to have one, but for a purebreed from a decent breeder your looking to pay atleast 800 bucks for one.
heres a pretty good site with alot of info on them
http://www.staffordmall.com/