Not completely true.  The Red Army owed it's mobility to the massive infusion of truck and Jeeps the US sent its way.   Their massive losses on the battlefield were due in a very large part to the Soviet indifference to casualties - to say nothing of their penchant for murdering their own people.  Also, since you mentioned late-comes to the party let us not forget that the USSR was a Nazi ally and committed all sorts of atrocities there, such as the Katyn Massacre.   They 'joined' our side barely six months before the Americans who, it should be noted, basically armed everyone else and defeated Imperial Japan virtually on their own.   As to cheating Russia - how did that happen?  Not letting them absorb all of Europe?