Communism gets a bad rap because people confuse it with totalitarianism. Communism isn't a social state, but an economic one. Communist countries in recent times have been creating totalitarian states under the guise of economic communism, which was always doomed, because economic communism is only possible when all humans work the same amount (ie, nothing) due to the pervasive human notions of fair effort. Economic communism is only possible when the work required to live with a high standard of living is at the lowest common denominator, which is only possible with solar powered robot slaves. These robots will be created by people seeking profit, but over time as they proliferate, the fiat required to purchase them will become less and less meaningful to those earning them. We're still a loooooooooooooong long long way off from this, yet.

The USSR and China were trying to make a communist economy work by becoming totalitarian states (force the people to work evenly). Since communism applies the cost of failure to the whole population instead of the individual investors in a capitalist economy, much of its success is dependent on the dear leader, while it's been shown that the more people involved with a decision, the more accurate and efficient the results - the free market is an example of this. In both economic systems, a good product is enjoyed by all, but a bad product is suffered by all in communism but only the investors in capitalism (over time). Thus, there is faster progress in capitalism, because losses are minimized to those taking the risks. Poor decisions in communism means losses are multiplied to all, when there really can't be any losses at all for communism to even work.