There is a lot more to choosing a puppy than the appearances of the parents. This is true in any breed. With Pit Bulls, or the actual breeds commonly referred to as Pit Bulls, if you are looking for a pet, you especially want to stay away from lines bred for fighting. You really need to look at health, allergies, I don't think Pit Bulls have the joint problems larger breeds do, and most of all temperament. I once had 2 young Labs. Lola was the best looking of all the 16 1/2 I have had, a very solid yellow color, big square head, heavy frame, tapering tail, and all that. Peggy had an improbable dark reddish tinge to her coat, a small pointy head, long droopy ears, droopy eyes, a small pointy head, and a frame that left her a head taller than Lola at the same lean 70 pounds at a year old. I wondered if somebody snuck some bloodhound blood into their field Lab line. Lola was a failure, shying away from such dangerous things as clothes baskets, and quickly washed out of dog guide school. Peggy only feared missing her next meal, and graduated as a dog guide and likely had a good career.
For more general info on choosing a dog, see
Articles Some of the Pit Bull owners here may be able to give more specific info on them.