I've been using this monitor since last November and I haven't had any problems with gaming. I am not, however, extremely sensitive to ghosting, lag or color reproduction, and I have not noticed anything like that. I do not play a lot of FPS - mostly Skyrim. Hope that helps some.
This monitor is great for gaming! Battlefield 3, Skyrim , Borderlands 2 - all look great without any noticeable flaws. I havn't had it long enough to have played anything else yet.. Like Jack stated have some serious gpu muscle if you want to run high levels of detail. I have an i7-2600k at 4.5 Ghz and two GTX670's. Fluid, flawless gameplay. One great thing about this monitor is you can set different display sizes to suit older games - i.e. 4:3, etc. High res digital pictures are jaw dropping! awesome monitor - even at its high price.
I use this for gaming all the time, BattleField 3, Borderlands 2, Diablo III, Resident evil 5. No Drawbacks from what I have seen. outstanding performance in my opinion. running it with EVGA GTX 680 Quad Sli on Rampage iv Extreme MoBo, 3930k at 5.2 Ghz, 2x 480 GB Intel SSD Raid 0. NZXT 810 switch tower with all EK cooling Products. I would say the 2 best monitors out there with the right performance/price ratio are the DELL U3011 and HP zr30w.
I use it for gaming. I have played Tribes Ascend, Trine 2, Starcraft 2, and the latest Elder Scrolls game. It is great. Folks have said that there is an input delay, but I don't really notice it. It is amazing. Make the jump. You will not regret it.
I would highly recommend pairing it up with a adjustable desk mount (Ergotronics). I use SLI 460s and have not had any issues so far.
Some people say there is input lag and ghosting but I do not see any. Works great for me. You need a LOT of GPU for it though. I use SLI 470's and they are starting to show their age already at 2560x1600.