I've noticed that if I'm not looking for something wrong with the monitor, then it almost doesn't matter what monitor I'm using. At first I notice things, but the brain adjusts quickly and then I get lost in the game or whatever else I'm doing. That said, I love my monitor but I remember loving my last ones just as much and they were TN panels.
I'll give an example. Yesterday I calibrated my monitor with a Spyder 5. After calibration, the colors became more natural and everything was corrected and looked great. I switched it back to non calibrated profile and there was an obvious green tint to the whole screen, but I never noticed that before, and if using the monitor for more than 2 minutes, I stop noticing the green tint and everything looks normal again.
I switched back to the calibrated profile and again took notice of the accurate color correction, but after a couple minutes I stopped noticing that too.
My last monitor was a 27" 1080P TN. It has huge pixels that if I were to go back to now, I notice right away. But when I used that monitor I remember it being crystal clear and very nice and it would be that way again if I were to use it for an hour or so.