Mao's sin is he only cares about his legacy will live for every in history. "他的腦子直到臨終都保持清晰,清晰的轉動著一個念頭:他自己,和他的權力。" He does not care about the people. Ironically, this is exactly what destroyed his legacy, if there were any possibility of one.
The fundamental difference is Mao is a selfish bastard. 彭德懷、周恩來、林彪 and Deng are not. They care about the people.
Being a political bastard may be necessary to get all the power to get things done. Deng could be one example as well. However, Mao is a selfish one. Deng thinks more about the people. Being a bastard is the mean. The difference lies in the goal--self legacy or best interests of the people and nation.