User blog comment:N7/Battle of the First Person Shooters - Halo: Reach vs Call of Duty: Black Ops/@comment-1840523-20100802153420

AC:B is a wierd one, you're an assassin, and while taking down your targets you have a group of assassin 'brothers' who can gather intel for you, assasinate guards/other targets and fight alongside you in big battles

Gears of War is just a plain old shooter