LCD TVs are very slow (even if they are lit with LEDs instead of lamps) so the manufacturers make it confusing to judge whether each set is actually faster or just has processing to make the effect on the picture less noticeable. I would suggest going with 60hz and turning off all the video processing features for gaming. The picture is often better with them off for TV and movies too.
There is a tiny bit of a lag from when you press the button to when the action happens on screen, but it's in milliseconds. I've experimented with firing a shot in a game and flipping the motion settings back and forth. The difference is very small. Most people probably wouldn't notice it. It doesn't hinder game play for me but if I'm playing competitively in a fighting game or fps. I turn it off.
Sucks having OCD though. I wish I had a set with a higher refresh rate with absolutely no lag.