What have been the major accomplishments and failures of command economies?

Please help ASAP any information that anyone has would be greatly appreciated, thank you and god bless.

A command economy uses a country's resources more efficiently and is capable of providing a more equal distribution of wealth. It is not as vulnerable to economic cycles as a free economy.

They are not as productive as a free economy because there is little incentive for the population to produce. Even in private owned businesses, heavy handed government controls become a limiting factor. Russia has moved to a free market system and China has shifted in that direction considerably. Two countries that remain in command economies, North Korea and Cuba, have made little economic progress.