I know Mao gets put up there with most evil dictators of the 20th century, like Stalin, Hitler, Pol Pot. However, someone recently told me that he had shared power with 3 other people known as the Gang of Four, and I was wondering what was more accurate.
It's....completely inaccurate.
The Gang of four were Mao's wife Jiang Qing, Zhang Chunqiao, Yao Wenyuan, and Wang Hongwen. They were radicals during the cultural revolution and was only really relevant for the last decade or so of Mao's life. There was never really any power sharing, they were tools used by Mao in the political struggle of the cultural revolution.
The gang of four had little/no personal power-base, and was entirely dependent on Mao for political backing. Mao promoted them specifically to attack his political opponents without getting his own hands dirty. The gang of four would launch vicious ideological attacks on opponents. While effective, the gang of four themselves became hated for how far they went. Without Mao's backings, they were relatively powerless. Within a month of Mao's death, all four members were arrested and removed from power by other members of the Politburo.