The first answer is absolutely correct with respect to the impacts of their rule on their respective countries. I want to talk a bit about their impact on the world.
Hitler, in particular, had a huge impact in that he (more or less) started WWII. Because of this, you can say that the result of his rule was nothing less than the whole second half of the 20th century (and aspects of today).
For example, without WWII, Western Europe is not devastated and the US and USSR do not become rival superpowers in the Cold War. Instead, you have various powerful countries, including Germany, France, and Great Britain.
WWII totally shaped the world we live in and that is an important result of the rule of these two men.