Communism will never work as a government, and it is a horrible idea to even try to implement it. In a community of ~500 people, that's a completely different story (almost utopia-ish even).
Why won't it work? Well, just go to any shared kitchenette and chances are the stoves and microwaves would be messy as hell (that odd ones here and there doesn't count xP).
Anytime something is "shared", an "user" will abuse it unless there's dire consequences.
Capitalism will not work as well as a government (good thing we have Federalism) since it will lead to Technocracy among other things. Capitalist always view the market as an ever growing entity, which cannot be true (do I really have to explain?). Given half the chance, they would ruin everything in the name of profit. Dunn's formula took decades to take effect, and then a formula that look at widow-survival rates got used and relied upon that ended up with the sub-prime blunder.
Democracy has its failing too since it's "us vs them" at the international level as well as the grassroot level. Non-citizens are only good for exploitation in a Democracy.
In short, Communism isn't evil, just an horrible idea to implement to non-hive mind creatures, they work wonderfully for say bees, but not human.