All official unions are essentially controlled by the Communist Party of China. However, this is changing and labor law is dramatically improving.

Basically what happened is that China developed and expanded its economy very rapidly from the 1980's onward, and due to both corruption and opportunism in the Party, is largely pulled most of the working class of China into a poorly regulated private sector controlled by the national bourgeoisie (formerly kept under much tighter control in the Mao era.)

The way forward for workers in China is thus two-fold. Recent campaigns of corruption and major reforms to China's labor law (which have given unions far more independence and increased employer accountability) have shown that one side of the struggle for workers' rights is within the CCP where Chinese Marxists are pushing for a return to a more socialist approach to labor. The other side of the struggle is outside of the CCP, among workers who are increasingly agitating, organizing, and striking in militant ways.

As for your second question, workers who remember the Mao era have mixed feelings. Many look back on it as an era of stability, when people were ensured basic dignity and the economy was more under popular control. However, many workers also remember it as a time of great poverty and scarcity. The era of the Cultural Revolution also left a bad impression on much of the working class due to its dire social consequences for many, which hurt the reputation of the more classic "Old Leftist" tendencies of Chinese Marxism.

Thus, the way forward is still debated amongst Chinese Marxists. The more militant ones advocate for independent organization from the CCP as with the underground Maoist Communist Party of China. Many others, however, are more focused on reform, increased democracy, and accountability within the CCP. This is often the case with the Chinese New Left.