Being one of the people that has read Marx's writings and having a business economics background I have done a lot of research when I was younger regarding the benefits and drawbacks of communism....basically the problem in communism is people, the theory and excution is only truly valid if everyone pulls thier weight your two largest problems in communist societies are greed and lethargy both of them cause imbalance in the system this is the essential paradox of the theory. Also this presents the reasoning that in a small society (where everyone has contact with the other people) these urges of greed and lethargy can be monitered and those taking advantage of the system have a higher risk of being caught thus preventing them from taking advantage. As for your statement about Russia, while it's homelessness increased it was primarily due to those that took advantage of the system of communism for so long and all of a sudden they actually had to participate in the economy and work hard to earn money that was given to them before...it was a big change but definately from what I see when I am there (been to moscow and st petersburg multiple times) it is a change for the better.

Before you mention China remember that the chinese have had FTZs since the mid 80's which are run as strict capitalist societies and have turned the FTZs into the most densly populated areas in the country and also made the Buick one of the best selling cars in china.