I own both but I play Killzone 3 way more don't know about you but very few of my friends own ps3's but I love multiplayer and I like KillZone 3 much more. Bigger Maps both games have solid controls. Limited options for character in both compared to black ops, battlefield and homefront, but still plenty to choose from both are arcade shooters, I like KZ's campaign more, KZ feels a bit more open like battlefield and Homefront but retains fast pace. Crysis 2 just feels like a futuristic form of COD.