I don't know which of these two games i should buy.I like both of them, but i can't decide. What do you think?

I have curiosity about this. Please give me your opinion. For you waht is better, more powerful and has better games?

Hey, if you take the time to read this, please help me! I have my x box 360 but i dont' know wht games i should buy. I like FPS and RPG games, and i like games that have a large longevity, not those ones that you complete them in a day. So please, help me deciding which game i should buy