Lenin rose to power after Russian society overthrew the Czar. He took control of a democratic republic. Though he practised some communist ideas, his principles were more socialist hence the name Union of Soviet Socialist Republic. He was more of a socialist dictator; he used socialist ideas to complete economic control on land and business.
Stalin rose to power after Russia Society had already been under a dictatorship for some time. He was the leader of the communist party. Stalin maintained economic control in socialist way though he used his communist ideology to violently retain his power.
Lenin was not a murderer for starters. He had ideals rather than naked ambition. He was a visionary leader with followers who held the same ideas and followed for that reason, and to improve their lot, rather than following from sheer terror or a liking for meting out brutality, as Stalin's followers must have been to carry out the extensive atrocities over such a long period.
Lenin espoused the political reasoning of Marx and carried out the socialist principles on which communism, the equal sharing of resources, was based. It is not brutal Stalin who is revered today whereas Lenin is still regarded as the father figure and a creator of modern day communism.