Baymule
Herd Master
X about a 1,000,000,000!!!!IMHO find the owner, or take to a shelter. "Breed doesnt make the dog all the time". True. But sometime breeding WILL come out. Just as LGDs instinctively protect herds, and aggressive rabbits are culled from breeding lines, certain behavior traits CAN be there, regardless of the treatment. Pits were developed to be viciously aggressive. Not all are. They can be very loving family pets. But sometimes a loving pet can get a (unrealized) trigger and genetic behavior can rise to the surface. It only takes an instant for tragedy to happen.
I personally might consider keeping. Heck, my dog now has pit mix. But it's just me, out in the country. If I had four precious bundles of boisterous energy around, no WAY I'd trust generations of genetics to be overcome, no matter how loving the dog seemed in the beginning.