All to true.
I recall going over to a friend's house once to play CoD4 on his PS3. Watching him play, I was amazed how he and another player would be facing one another, and I could literally count the second or so it took for them to line up a shot. Most kills occurred at waist level, or higher if the player kept his reticule slightly higher, using the strafe keys to essentially provide bearing. Sinping kills occurred when the target was stationary.
We connected an experimental mouse controller to his PS3 so I could try (I absolutely cannot play FPS on a console.) And proceeded to point-click through the match. I consider myself a mediocre player on PC, but I felt absolutely god-like with a mouse on his PS3, racking up head shots and being able to accurately shoot on the move.