So far I tried out gw2, the witcher 3 and star citizen. they all play very nicely.
gw2 fps wasn't affected
the witcher 3 got a little dip going from 1080 to 1440, but it is so much better without stuttering and the colors are wonderful.
on star citizen strangly enough I didn't notice too much of a performance loss if any, and I would keep 30fps. another odd thing is that you really don't notice low frame rates.
Never been on an IPS panel, and I must say I am impressed, black is black and white is white, it's like the picture has a lot more depth.
Best money spent on a monitor, I just hope it lasts long enough <.<