I didn't give much background because I figured those who had an opinion would state it, and those who didn't know much about Mao wouldn't bother posting. Giving background would've biased everyone from the start. Here's my take on Mao. I could play devil's advocate and take the other side, but I'm too tired to bother.
China doesn't exactly have a history of good, equitable, just government. Heck, I would've supported the Communists, too, at the end of WWII. I understand why many (although not on this forum) people think Mao was great because he helped get rid of the Japanese. The Japanese committed atrocities against the Chinese as horrible as the Nazis committed against the Jews. Others think Mao did a good thing when he got rid of the corrupt Kuomintang (KMT), the ruling party at the time. But as to the KMT, he replaced it with a system that eventually was no less corrupt. At the end of WWII, though, changes were needed in China and Mao was the best option available.
And then he went crazy with power. Abraham Lincoln said, "Almost everyone can withstand hardship. If you want to test a man's character, give him power." If we judge Mao by that standard, he fails spectacularly. Meanwhile, the Chinese people were like the proverbial frog being slowly boiled in the pot. By the time most people realized how horrible the new regime really was, it was too late to change it. Mao progressively introduced more and more purges, directed against larger and larger portions of the population. In the end, he had destroyed the nation's economy, historical artefacts, way of life, and traditional culture.
One of the purposes of government is to safeguard the welfare of its people. Mao cared nothing about China or its people. Mao cared about Mao. He preferred to let 27million (or perhaps it was as much as 47million, depending on your source) people die in the Great Leap Forward because he wouldn't admit he was wrong. The farming error occurred simply because everyone was so busy melting down their doorknobs and kitchen knives in Mao's steel-production scheme that the (bountiful) crops just rotted in the fields. The famine was completely man-made. In addition, the Chinese countryside was completely stripped of trees and the steel produced was worthless. Peng Dehuai respectfully suggested a change was needed because the people were having a rough go of it, and his life was subsequently wrecked by Mao.
Mao was good at getting others to do his dirty work for him. Anyone who possessed an independent thought was removed, leaving China in the hands of the stupid and uneducated. Because of his skill in pitting people against each other, he seemed to be above the fray and let others take down his enemies. He destroyed the economy and openly admonished the citizenry to deal violently with whichever section of the population he was targeting for destruction at the time. During the Hundred Flowers campaign, he encouraged people to speak their criticisms of the government and promised that there would be no harmful consequences to those who did. A trusting population, believing that the government was good and willing to listen to its suggestions, complied. A year later, he waged a campaign to ruin all those who had obeyed his instructions.
Not only was Mao bad to China, he's poisoned other countries. Pol Pot went back to Cambodia from a meeting with Mao, moved everyone (over 95% of the population) out of Phnom Penh, and pretty much destroyed the nation of Cambodia. This, based on Mao's advice. I think the Shining Path guerillas in Peru were Maoist. And right now the government of Nepal is fighting desperately against brutal Maoist rebels (the government soldiers aren't beyond brutality themselves, though).
If you compare it with governments past, China's government today is fantastic. The people are freer than ever before. They've got a lot to fix, but looking at how far they've come in the last 40 years, they're doing pretty good. The best thing Mao ever did for China was die.
