State communism: literally solves none of the problems it identifies with capitalism, with the additional issue that because of poor communication of price signals, it can't recover from economic declines, leading to mass starvation and other catastrophes. Libertarian communism: two of the really good things about capitalism are value exchange and capital reinvestment. These are natural incentives that lead to economic growth and net increases in standards of living. By rejecting them, libertarian communism lacks the incentive framework for this progress, and probably wouldn't sustain itself.