Most of my information on China comes from my father who was born in China, and was very well studied in Chinese history, although he left when he was young because of the famines during the Great Leap Forward. The part of history that he emphasized to me, was that in spite of the Great Leap Forward and Cultural Revolution killing tens of millions of people, communism was still much better than what came before. There was constant famine before communism.

I'm not so well versed in Chinese history myself, but I believe this narrative. One thing that confirms this is a graph of China's population. It shoots up after 1950, and you can't really identify either of these major catastrophes by looking at a population graph. The obvious explanation is the population shot up because people had enough to eat, notwithstanding these two discrete events.

Would Chiang Kai-shek have done better? The Guomindang certainly wanted to institute land reforms that would have benefited peasants (the vast majority of Chinese) without the central control of communism. On the other hand, it's not clear that the Guomindang would have had the power to actually implement these policies.