I'm friends with everyone leftist, even if they hate each other. I can feel comfortable among anarchist, tankies, socdems, new age leftists, reformist, etc. Because I know what our common objective is and I just can't care about the subtle differences. So I know the anarchist side of the story as well as I know the tankie side.
Being myself an active member of the social movement in my country and actually having watched modern day anarchist working with modern day communists I can say without any doubts that no version is true. Probably both starting arguing about stupid shit, and actual personal problems disguised as political problems, when they should had focused on the real enemy. But anyway I'm thankful for ALL who fought against fascism in Spain, anarchist, communist, republicans... I thank the international brigades, I thank oswell and I thank the soviets and stalinist. They all put their lives on line to stop fascism.
I just despise such an unproductive and harmful division of the left for shit that just does not matter when the true enemy is so big. And sometimes I just see a lust for internal division and eternal losing in such behavior.