You are correct that while labs tend to be more social pitbulls have been bred to have a lower 'trigger' level with other animals and to be more willing to fight hard and be less tolerant of others even though they love people.
I would suggest trying this puppy aptitude test
http://www.workingdogs.com/testing_volhard.htm
and checking the scores against the bottom results area and then, if the results fit a personality profile you feel comfortable with, start the pup in puppy kindergarten, work on safe socialization so the dog meets plenty of other dogs and learns to like them, and do lots of obedience training which can include fun stuff like agillity as well as control type exercises.
The more training and socialization you do the easier 'teenage' time will be and the better the dog should be as a mature adult.
Hope this helps you!
Dog Expert:Rescue, Train,Breed,Care
30+ yrs dog home vet care & nursing, rescue, behavior&training, responsible show breeding, genetics