Game Debate to the Death! Mass Effect vs. Assassin's Creed

Destructoid writes:

"Now it's time to continue the console-by-console odd debate tournament series into the Xbox 360 library of games. This week we have two games that both have plenty of story and gameplay backing them, but each with completely different styles and settings. One takes places out in space with guns and aliens of the future, while the other reaches back in time and explores the Middle Ages with melee combat and stealthy controls."