Historical evidence shows us that capitalism is clearly more efficient than communism. Unless we try to claim that communism has never been truly implemented, there is very little to imply that it is more efficient.
If we look at history, we see that no communist country has ever been able to deliver what capitalism has delivered. Communism was supposed to make everyone equal and give everyone a good standard of living. It failed miserably to do this in every country where it was tried. We need only look at standards of living in Cuba and North Korea to see that this is true.
Of course, the Soviet Union did improve its standard of living over what had existed in tsarist times. However, it was not able to deliver enough in the way of consumer goods to keep its people happy. At the same time, countries like South Korea rose from poverty faster and became richer without using a communist system. China, too, has boomed economically once it got rid of its communist economic system.
Communism will never be efficient because it does not give people any incentive to work hard and to innovate. People are inherently selfish and self-interested. They want to get rich. If they are given the opportunity to do so, they will devise ways to give consumers the goods and services they want. This profit motive is what makes capitalism more efficient than communism.
Communism is by far the more efficient means to usurp power from the people when its initial appeal for the working class is the opposite. The pseudo-capitalism we have in the US is not that far off in terms of undermining the masses.
in terms of economics, there are a number of factors for success depending on one's perspective. I think a specific definition of success is needed the compare the two.