>>8
Didn't the Makhnovists rape the Whites, and give the Red Army a run for their money? From what I heard, they entered a temporary alliance, and the Bolsheviks betrayed them upon destroying the counter-revolutionary armies.
Also, the Spanish anarchists held their own for quite a substantial amount of time. But again, the Stalinists in power fucked them over, and refused to aid them against the Fascists. Had they abolished the Republican state when they had the chance (instead of participating in it later on...), that wouldn't have happened.
One more thing. Anarchism/communism is not a utopia. A utopia means a perfect society, with no pain and suffering whatsoever. Even the most perfectly realized communist society would still have its problems, due to the reality of human existence. People would still get ill, there would be disagreements within a community, there would still be crimes committed by sociopaths, people would die... but it would be a thoroughly human society, free from illegitimate authority and coercion. Not quite a utopia, but definitely a more enriching and fulfilling society.