"Kill one man and it's a tragedy. Kill one million men and it's a statistic" paraphrased joseph stalin.
All you really need to know about the man imo.
Recent bbc program for us englanders. WW2: 1941 & the man of steel
http://www.bbc.co.uk/iplayer/episode..._Man_of_Steel/
To be honest I see no real difference between racial ideological extermination by the nazis and political ideological extermination by the soviets. But if we're going by pure body-count alone, stalin makes hitler look like a rank amateur for what he did to his own people before, during and after the war.
I think we can argue that hitler was undoubtedly insane, where stalin seems a whole lot more calculating in his logic right from the start. Both are evil, but the evil of rabid insanity, though terrible, has little to compare it with the evil of cold deliberation and the rationale implicit in what I paraphrased above. Which for me sets the bar for assessing the products on nazism and communism and the men (if you can call them that) who rose to pre-eminence by and through these totalitarian ideologies.
Nazism brutalised germany in purges lasting a decade or so, and europe in a terrible war. Communism brutalised europe for almost fifty years, and it's own country as far back as 1918.
Not much of a credit to humanity, either of them. But history is littered with such men, to whom other men are as less than chaff.