How important is response time in monitors and how distinguishable is it?

I'm currently looking for a new monitor and I have the ASUS MG279Q, the ASUS PG248Q and the ASUS MG278Q. Now, my setup is not the highest end, but decent with an i7 and a 1060 3GB, and there are three concerns I have currently not found an answer for:

1. The (potential) difference in quality between the MG279Q's IPS panel and the MG278's TN panel
2. And the delay difference, the TN panel having a 1ms response time and the IPS' 4ms
3. If my setup can even handle 1440p/144Hz (I don't need to play on the highest settings, nor do I need to reach those 144 FPS), in which case I would tend more towards the PG248Q

I'd love to upgrade towards 1440p as the screen real estate would be good for working (which I do a lot on the PC) and I would, I could later upgrade my GPU if the performance in games isn't satisfactory. I think my setup wouldn't have any issue handling day to day tasks and if need be I can play on lower resolutions or lower graphic settings. Also I wonder how large the difference between the IPS and TN panel is and if it's noticeable, particularly with colours.

Does anyone of you have experience with the subject or with the monitors named in particular?