Interesting conversation. This is the way I look at it. Some people might get upset, but I'm just being honest. I would not personally adopt 'powerful' dogs from a shelter if I had young children. When I say 'powerful' I just mean a dog that has a very strong bite force. Simply because you don't know the exact history and because of the potential damage it could do. Again that's me and just the way I see it. You just don't know. If the dog doesn't have the capacity to due tremendous damage than that's another story.
As for bite force or potential damage, I had a black lab that around my family was great. My son (2 at the time) would crawl all over that dog, take his food, hit him with toys, chew on his ears, etc and that dog wouldn't even open his eyes if sleeping or bat an eye if awake. Yet you let anyone from the outside world into his reach and he would bite and I mean BITE. I had a friend come over and whenever someone was new I would always introduce them a few times till I knew they were okay. Well this friend comes in (6'3 345lbs) and Bob (the lab) grabs him by the arm and drags him towards the kitchen shaking violently.
Not normal behavior from the worlds most popular (family) dog.
IME all the "aggressive" breeds I've encountered have been pretty tame. Sure there were a few that didn't like kids, or cats but for the most part pretty good. The worst I saw was my brothers chow/german shepherd. She was just a straight up mean dog. I would say 99% of the time mean or aggressive dogs are that way because of humans. Whether it be to guard, look like a badass, or to fight. But there are always going to be the odd ball out like my black lab was. Dogs are like people, they have personalities. Not every person is nice and gets along with others.
In the time we have had the pit we have had great success with him and the kids (2y/o 4y/o & 7y/o). He and my youngest play the most. They love to wrestle and play tug of war, and the pit likes to pin her while she laughs her ass off.
We are happy with our choice in the pit, the only draw back with him is when he gets to running in the house and knocks people over, but that's usually a quick 10-15 second sprint and then he chills out.