The official stats show that most people didnt kill both brothers, but doesnt indicate who killed one brother or who killed neither. Personally I spared both. I might have killed Danny, but I read a spoiler in advance and knew Clem would be watching, so no way I wanted her to see that. Not killing Andy was both an act of mercy (he was so pathetic kneeling broken on the ground like that) and as a way of seeing a much more epic conclusion to that scene.
So what about the rest of you? Kill both? Killed one, if so which one? Or spared both like me?