I never bred Am. Staffs. Janet's had personalities more like bullies though.
True APBTs were a handful as far as dog aggression. Some got a long and others didn't. It was very dependent on the individual dog. I've broken up my fair share of fights. They have very high drive and when they don't like a certain dog, you have to be so very careful when you're moving them around. I had one pick up chain-link and go right under it to get to a dog a few kennels down. Same dog chewed through a crate to try and get to the same dog. Those two were horrible for each other.