As a GM: in one, the overarching story is (Stop here if you are a player in either of the ARD library games, you know who you are) a mage destroying towns which should lead into a conflict between gods, and the eventual goal is to stop this conflict. Until then, they have a lot of freedom in what they do: I offer them rumors, goals, and hooks, then they choose what to follow or make their own way.
The other one has a huge war looming that they want to stop, so the players do sabotage stuff to the evil empires but have a lot of freedom.