Both were great generals, no question. But saying Napoleon was an overrated tactician is just not true, in almost every battle his tactics have been superior and even after his retreat from russia he managed to win at least tactically against greater armies.
He was both a great tactician and strategist, though the question of great strategist depends on time lapse, was invading russia a bad strategy? yes, but on the other hand his logistical ingenuity proved him to be a good strategist again and again.