I cannot speak for China, but Cuba has many democratic aspects that make it (IMO) more democratic than the United States, in ways that matter.
We Westerners are trained to think that "democracy" means "democratic republic" on the liberal, Anglo-Saxon models. And while no one would argue that this exists in Cuba, there are other democratic elements, which I think matter more than being able to choose which member of the ruling class will screw you over for the next four years. Democracy in the workplace and in the living space are extremely important in day to day life. We in the West live under a daily tyranny of petty despots who rule our jobs and our homes (unless you work for yourself, or own your own home, although even then unless it's paid off your life is still controlled to an extent by your creditors), and democratizing these does more to help people than being able to pick your representative and your political leader; although Cubans get to do the former as well. Their National Assembly is not unlike Western parliaments, and their representatives are democratically elected. And this democracy is more fair than ours: without accumulated private wealth to influence elections, Cuban representatives are true representatives of the people, of a politically literate and organized populace. Half of the assembly comes from local nominations, the other half is nominated by labor unions, student unions, and other such organizations. None of these "I'm not interested in politics it's so boring" lobotomized morons who eschew politics in our society today.