Personally, I would consider Stalin worse. This may be a surprising statement to hear from a communist, but the communist movement is highly divided and ultra-leftists like myself and Stalinists share a mutual dislike of each other's methodology. Stalin's regime was a state capitalist police state that completed the creation of a new bourgeois that had been begun by Lenin and caused famine, great oppression, and more deaths than the Nazis caused. It was more destructive to the proletariat's freedom and ability to survive than Nazi rule in practice, and, with all its nationalism, almost as bigoted. All this was about as socialist as Airstrip One.
Well, there's my view. Let the debate, flaming and swarming by angry, ice axe-wielding MLs begin.