Would you like watch youtube on 720p 60 fps or 1080 24fps? 4k would look sharper if you compare 1440p with 4k on same panel size. Problem with 4k is having games or software that scale nicely with it. (ex: really small cursor with 4k resolution). And GPUs are not powerfull enought to stabily drive 4k resolutions. Most gamers would prefer having higher refresh rate for smoother gaming experience. Having 144hz monitor for movies and work doesn't make sense. So yeah, 4k is good for work and media, but not gaming.
Doesn the scale in Windows 7 or 10 work well? Like making the 4k monitor have bigger font and buttons etc without losing the resolution? Also, there is only about 2 choices if you want 144mhz, 2560x1440, IPS, Gsync monitor....
Having a solid 60fps in games at 4K hasn't really been a reality so far unless you had a couple of high end cards running in SLI. I'd choose 100++ fps at 2K over 60fps at 4K any day.
It is becoming a reality now though. 1 gtx 1080 is hitting most games around 60fps and the 1080ti will obviously be faster, not to mention 1080 SLI etc.
OS? from 8.1 it probably scales nicely. But not all games and software are scaling nicely. Especially older ones.
For pure gaming 1440p/144. No doubt. For people who game but use their PCs more often for other things, 4K/60 is probably ideal, especially in larger screen sizes simply because the image is so clear. I've always been fine with 60FPS so I am absolutely loving the 4K res (43") even with it hammering my video card. I stopped playing AAA games until I get a 1080 but meanwhile, slightly less taxing and older titles look phenomenal at full 2160p. I can still play AAA in 1080p and some in 1440p res but I want to savor the 4K glory later (if the GTX1080 can handle it). Simply browsing the internet looks amazing. I never realized so much web content was in such high detail. Text/fonts are amazingly crisp. I can never go back now.
I recently upgraded my monitor....my reasons were simple....BIGGER SCREEN!! lol. Had a choice between 1080p or 1440p for a 27" monitor or staying 24" and going 144hz. Given that my pc is aging (or rather not top of the line) I knew that most of my games ran at around 60-70 fps on my original 24" 1080p monitor. So there was no point going 144hz as I was going to lucky to break 60fps at 1440p. Just have to be realistic that im stuck with 60hz until I upgrade my pc.