In Nazi Germany Hitler was The Fuhrer and he didn't pretend that he wasn't a dictator, but Stalin used sly tactics and fear to pretend he was democratically elected by the CPSU. At the end of the day, these two authoritarian governments were both despotic, stemming down from these two guys, but then did the mechanisms of chain of command differ between Nazi Germany and the Soviet Union? Was there any actual democracy and voting at any level of government in either state? Local or regional? For different departments of government? Or were they identical top down totalitarianism governments starting with Stalin and Hitler with no meaningful differences, except for Ideology?
The similarities only seem to outweigh the differences to a westerner who is not used to brutal forms of government. Stalin's USSR and Hitler's Germany were both ruled by despotic, totalitarian leaders, but that does not mean they were the same. Their methods of control were different, and those differences reflected the societies in which they ruled.
Stalin took control of a vast multiethnic empire mostly populated by uneducated peasants. His methods borrowed heavily from the the Tsarist government that he replaced. He created a personality cult that was a secular facsimile of the religious devotion that Tsars of centuries past had inspired. His totalitarian state and security apparatus pervaded into the daily lives of every citizen. Everyone was a potential traitor. And significantly, the danger was greater the more important you were. Communist party and military officials were at greater risk of being purged than the average peasant, because competent people represented a threat. The communist revolution was all about overthrowing the old power structure. Anyone who held any power before the revolution, any factory owner, military leader, etc was highly suspect and could be be killed or sent to the gulag on the slightest suspicion. In short, Stalin sought to overthrow and replace the existing power structure, and anyone who was part of the old guard was not safe.
In contrast, Hitler's Germany was a fundamentally conservative revolution that preserved old power structures. Germany was highly educated and industrialized before the Nazis came to power, and Hitler intended to use this to his advantage. He worked to court industrialists and military leaders rather than overthrow them, except when he couldn't avoid doing so. When the war went south, so did his relationship with the generals, but they were merely fired rather than shot. He ruled primarily by love rather than fear, promising the average German economic advancement as long as they supported him. So long as he was a good little citizen who didn't publicly dissent, the average German did not fear the Nazis in the same way that the average Russian feared Stalin. In short, Hitler was a pretty good leader as long as you were a German Aryan who held the right political persuasions. Towards the end of the war the power relationship between the Nazis and the average German devolved into a more fear based system as the old incentives broke down.
So where are they similar? Both Hitler and Stalin were brutal leaders, who had no respect for liberal traditions or the rule of law, and who wanted to empower their nations by any means necessary. The difference is that they ruled very different countries with different cultures and histories, and their tactics were therefore very different.
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