Mao Zedong was far worse in the level of crimes he committed. Furthermore he also committed many massacres. Far more were killed by him than by Chiang. Think of the Great Leap Forward, the Cultural Revolution, Anti-Rightists Campaign and others which led to the deaths of millions. If you are thinking of personal morality and conduct then he is hardly any better. Also they destroyed many elements of the traditional Chinese culture in their Cultural Revolution. Several churches, mosques and temples were destroyed or defaced. Other historic buildings were destroyed. All of their ancestry books are destroyed. Old cultural practices and the richness of their culture was removed by the Cultural Revolution. The cultural heritage of the country was completely flattened. Even till this day many say the reason for China's social backwardness was due to the fact that the moral and cultural fabric of the country was completely destroyed. Instead it was replaced by a strange Marxist perversity.
The good years of Mao Zedong's leadership were in the 1950s when China followed the Soviet model of rational central planning with expert advisors presiding over things. There was good economic growth in this period. After this he went insane and embarked on his Great Leap Forward which involved communes, de-centralised planning and without Soviet experts. They built many low quality infrastructural elements in this period. Many were killed in famine because the centre set targets for taking farm produce that left not enough food to eat and also because the communes took away any incentive for productive work. Only later did things improve only for Mao Zedong to again depress the economy with the Cultural Revolution where enterprises had political leftist fanatics in charge as opposed to people who knew what they were doing. In the 1970s there were improvements as they returned more again to central economic planning along the earlier model.
Chiang had always wanted to go using the market system. Look to how Taiwan became a developed country and very strong in economy under him. Also in the late 1940s the KMT were conducting land reform to give land to the peasants. In my view Chiang wanted to follow the same policy as the current Chinese government are doing now, only he wanted to do it from the 1930s and not from 1979.
Chiang was not pro-American. It is known that he had anti-American elements in his government and he himself was not always very trusting of them. It was not his desire for China to simply be an American satellite state. You can imagine that China would have allied with the US against the USSR until the collapse of the Soviet Union. In essence this is what happened even under Mao Zedong anyhow.