It's heartbreaking going on Petfinder and seeing all the pit bulls up for adoption. I'm just glad there're foster homes for them.
I hear pit bulls are more likely to display dog-dog aggression, as opposed to dog-human aggression. I've seen some real sweeties adopted out on the shows on Animal Planet.
From the pit bull discussions on Petfinder, there are some pit bulls that are vicious when trained that way but there are also some animals who are bred to be aggressive and aren't going to turn into lap warmers by any stretch of the imagination. Many pit bull lovers are very adamant in their posts that there is a definite genetic component that can't be ignored and they say they don't trust their pit bulls alone around other dogs. Then again, there are pit bull owners who've never separated their dogs and never had a problem. One sure way, though, to start a multi-page thread is to post that you want to put two female pit bulls together in the same house - the pit bull experts on the boards jump all over that and seem to consider anyone who does it as deserving of whatever disaster ensues.
Still, it seems they really have to be evaluated individually. One of my Dad's friends had a female pit bull who was a big [fear] barker who would urinate submissively whenever a stranger got too close. She was a big baby and adored my Dad. (A couple pieces of turkey bacon in the pocket didn't hurt either!)