What do you mean by functional Communist government?

For example my country, Hungary during the Soviet occupation was a Socialist country (Communism was the goal, but according to the state propaganda, we were in the stage of Socialism and not reached Communism yet). The economy had bad and better periods (for example the 1950s were the worst probably, the '70s saw some improvements but by the late '80s the whole economy was in a terrible shape).

There were no functional Communistic governments in the sense that that no country ever reached Communism in the Marxian sense. The attemtps like the early Soviet Union was not successful, and the Chinese version of Communism has almost nothing to do with Marx and Lenin.