Noam Chomsky summed it up best by saying (paraphrased): "The question is pointless; 400 years ago it would have been 'what is the best form of feudalism'. 100 years from now, capitalism and democracy will not exist as they do today."
The key is to make each economic policy dynamic enough to help the people governed by it. All forms have the capacity to work or not work, often at the same time.
Furthermore, capitalism in New York looks way different from capitalism in rural Texas. Communism in the USSR was vastly different from communism in China, Vietnam, Albania, etc. In the end, to make a binary choice in such a complex issue cannot be wisely done.