They are great dogs, I have a tosa x pit blend Swinford. He is only 25% tosa but has taken after the genes. He is great with the family (wife and kid) he is also good with my other 3 dogs but as you say can change at the drop of a hat and has shown that when we have been approached by other stray dogs and humans on our walks. Its like someone switched a power boost switch incredible power I understand what you are saying and your right about walking them I take him for a 2 + mile walk eveynight but I also work him with the flirt pole and he gets to tear round my yard with my boxer several times a doy.....you will have an excellent dog. Good luck to you