A:Answer It's personal preference. Personally, I'd take 1440 with higher refresh rates. Pushing over 100 frames looks amazing, and can make games look so much better from the smooth visuals. 4K is great, but even graphically intensive games can be hard for even high end hardware to stay at 60fps, without turning down settings anyway. 1440 looks great, and you can have the high refresh rates.
...or you could wait for that 144Hz 4K monster from Asus