I was JUST looking at mounts too. Was looking at Monoprice, but then came to this one on Amazon,
This will be my first mount, for a 64" TV.
Question for those with previous TV mount experience...once you mount it, I've seen the more expensive mounts allow you to slide the TV left to right within the rails, if you are trying to center it within a particular space. I am assuming with these mounts, you'd use the tilt to somewhat align your TV is you want to center it with a couch, for example.
Yeah... "tilt" is simply the ability to lean the top of the screen toward you. So you can line it up with your viewing angle (like, say, lying on your bed) and/or reduce glare from lights/sun.
This style of mount allows you to slide it left/right a few inches to "center" it as you describe. How far depends on how much space you consume between the vertical hangers. In other words, the left and right vertical hangers limit your left/right travel.
In my experience with 32 - 60" screens... its been between 6 - 4 inches either direction.