IMO dictators are not the same as democratically elected leaders, and should not be comparred using the same standards.
From a King (with absolute or near absolute power) or dictator's point of view, if you cannot be loved or respected, then it's better to be feared than to be made fun of. Thus, for an unpopular dictator to retain power, he or she leans toward legalist and oppresive type government.
As for Lenin vs. Stalin, we can judge the two from 1920's-1930's era point of view, and present day point of view. From the 1920's-1930's point of view, I think people would've preferred Lenin and the NEP (New Economic Policy) better, where peasants had greater freedom to hire labor and sell surplus grain. The increased agricultural production means people didn't starve.
Stalin, on the other hand, took the farms from the peasants and shot anyone who opposed him. His forced industralization though 5 year plans killed millions. However from present-day point of view, had Russia not done so, they'd probably have lost WW2 against the Germans. Without the rapid industrialization, Russia would've not been able to produce tanks and aircraft at such rapid pace.
Had Russia lost WW2, it's possible that the Germans would've wiped them out from the west and Japan from the east, resulting in the complete destruction of Soviet Union and the Russian state. Considering the Nazi's effectiveness in wiping out Jews, I think they'd have killed more than the 20 million estimated dead under Stalin's regime.