There is no doubt that the Soviets deserve more credit than the western powers for destroying the Nazi war machine. But it isn't like they did it out of any kindness in their own heart- they had to do it.
Also, in addition to the courage of the WW2 Russians, add in a good solid measure of fear of the political commisars and soviet secret police. Further, the Germans, by committing atrocities, didn't exactly endear themselves to many eastern europeans and ukrainians, and revenge became a motivating factor for many.
I just wish both sides could calm down and acknowledge that they both were needed to destroy the Nazis. Without the USSR, it is doubtful if the Western Allies would have tolerated losing millions more men. And without America and Britain, it was highly unlikely the Soviets would have been able to survive 1941 and 1942 without American aid and operations in North Africa.