How does Stalin do as a dictator?

Stalin has ordered the most executions of any dictator to date. A conservative estimate of at least 15-17 million. Purges and famines d the USSR, and people were becoming very anti-communist. Collectivization only furthered angered them, as they became unable to feed their own families. However Stalin was able to keep the USSR connected at the worst time of war (surprise attack), keep good morale within his troops in the longest battles (Stalingrad) and in the end, raise Soviet morale to the highest degree by winning the war. He made a near suicidal people become proud again, or maybe even prevented a revolt. After all this, Soviet citizens were mourning at his death. How does he do as a dictator?