So I have been gaming on this monitor for a little over a day now and I thought I would post my impressions. First of all, the jump from 60hz to 120/144hz is amazing. Really I can't explain how much of a difference it makes in aiming, fps games feel like your cheating aiming is so smooth. Switching my refresh rate back to 60hz to test the difference is excruciating, everything is choppy and my aim jerks all over the screen. I would say this is the single largest improvement to my aim that I have ever experienced, its better than switching to a gaming mouse or upgrading gpu's for more fps. Even at the desktop in Windows moving things around the screen or just moving the mouse is smooth as butter.
This is a tn led backlight panel the colors on it are horrible out of the box, worse than most tn panels I have dealt with. After a little tweaking in the menus the colors are on par for any other tn panel, its never going to be an ips panel as far as color goes but it does look good.
The display has some pretty neat gaming features like digital on screen cross-hairs, and anti-ghosting settings. Input lag is nonexistent, or close enough that I don't notice any at all. The build quality is typical Asus, everything feels solid and the stand is very nice. The stand adjust just by pulling the screen where you want it, no clasp or anything to deal with.
The display has a new feature from nvidia called lightboost, this was built to make 3d movies and games brighter. However there is a hack for this to work in 2d mode that makes the display feel like a crt without the flicker.
LightBoost HOWTO | The Blur Busters
With this hack installed the monitor is silky smooth when gaming with almost no ghosting, with smooth scroller installed in chrome I can read while scrolling. I really hope nvidia decides to support 2d lightboost and implements it so we don't have to hack it.
I was skeptical about 120hz making any sort of difference, however after using this monitor I will never go back to using a 60hz monitor.