Not ever seeing the men OR their dogs go, it's hard to really make any type of informed decision. Knowing what I know about jennys and mills, I would always favor a jenny over a mill as I believe it allows a dog to get in better shape. Given what I know about both men in their respective time, I would bet over a 10 individual run that Mayfield would win more than lose simply due to the quality of dogs that people were putting in his hands at that particular time.