BB, Hitler started WWII. Stalin merely reacted later and joined the war to tan Nazi hide.
You're obviously subscribing to the Russian version (and unfortunately due to peoples ignorance often the West's version) of history.
Stalin reneged on the molotov-ribbentrop (sp?) secret portion of the pact with the Nazi Germany where they divided Poland and the Baltic states amongst themselves. His ultimate goal was to get back all the territories Russia lost during and after the revolution. Germany attacked one week after the pact was signed on Sept 1, 1939. Instead of attacking Poland on Sept 1 as agreed to they attacked Poland a few weeks later on Sept 17th portraying themselves as protector's from the German invasion.
Fast forward to today - for the entire time Poland was occupied and later under the Russian brain-wash the Polish population was forced to teach their children about the German invasion and the Soviet "rescue action". You know, Katyń never happened, oh yeah ut happened but it was the Germans who did it, 70 years later (well technically when Yeltsin came to power), ooops, that was the Russians after all. Yet Katyń was just a small part of the Soviet atrocities committed against Poland and made "visible" due to the size of the murders in one place alone.
Today Poland is a free country yet people like you seem to know more about all kinds of anti-American conspiracies, such as 9/11 then you know about your own country being attacked by Germany and Russia in coordination spelled out in the secret portion of the molotov-ribbentrop agreement.
So yes, Stalin was a much worse tyrant and murderer because overall more people died under his regime than under Hitler's. Stalin came to power in 1924 and his murderous campain starter soon therafter. Hitler came to power (ironically in democratic elections) in 1933 and was dead by 1945. Stalin on the other hand continued leading a murderous regime until 1953.
All in all both were horrible and murderous thugs but Hitler was in power shorter time and he also focused on killing non-Germans whereas Stalin kept killing anyone disagreeing with him, Russian or not. There is no pro-Hitler movement in Germany today (except a tiny group of brain-washed rasists) but there are millions of Russians who still think Stalin was a good person.
Moreover, many people still believe in his/soviet version of the history, shockingly to me many of them are Polish, like you Seanus. So in my view, yes, without a doubt Stalin was much worst than Hitler was. Hitler was a Stalin in the making but he never reached his "full potential" (big sarcasm smiley if I had one).