Mao definitely has made some huge mistakes in Chinese history, but it does not make Chiang Kai-shek a good leader.
But there are some things Mao has done to benefit China now in a long term:
1. Industralization. It is the foundation of Chinese economic takeoff in 1980s.
2. Working on nuclear weapon. It avoids China to be threatened and controlled by US in millitary way.
3. Avoid losing the Korean War. I am sorry for people living in North Korea, but a divided Korea is better for China.
4. Help people to read. In 1950s, there are more than 70% of Chinese people who cannot read and write properly. In 1970s, the number dropped to less than 30%. Considering China has close to 1 Billion population at that time, it is a great achivement.
5. Rebuild Chinese people's confidence. What happened at China from 1840 to 1940s is pathetic. Being colonized by the west and Japan, people being addicted to opium, being raped by Japan. Chinese people picked up our pride and patriotism again, after 1949.
6. Taking back Tibet. Well, I know people will say "Free Tibet" but lmao, Chinese does not car. Actually, we welcome you to come visiting Tibet, it is a beautiful place.
But I have to admit Mao also made lots of terrible mistakes, but it does not change he is one of the most important Chinese politician in the modern China.