Obviously different games and engines have different feeling to how you maneuver the world you are in. Which game do you think feels the nicest to move around in? State your reasons why you feel as you do.
For example, I find Half Life 2 to be the best, and I think it is the crouch jumping and ability to hang on 2 inch ledges that does it. It makes you feel incredibly mobile and not having any legs gives you the wonderful illusion that you are actually running and jumping through the world, unlike left 4 dead and similar when you stand on a precipice and you’re doing the floating splits above it rather than actually balancing on it.
I liked UT99 because you felt heavy and the ground seemed wonderfully solid, in complete contrast to UT2004 where the entire world felt like one giant bouncy castle. Assassin’s creed had nearly limitless mobility, and yet could feel very restricted in some circumstances. Same with Mirror’s edge, which is why I like Half Life 2 better, personally.