For me, it's not worth it, since fluidity of motion is much more important to my gaming experience than the extra resolution.

Hence, I am still waiting for a 1920x1080 OLED monitor.

Isn't there a way to scale it up? Not in-game but on Windows? I have read that on Linux you can run applications in scaled mode (I have not tried it myself).

Maybe this will answer some of your questions.

You can, but it completely messes up your screen. Icons are either so tiny you can't read what they are or make out a picture, or they're so large it's ridiculous and half the screen doesn't fit on the monitor. But for many of the older games such as King Arthur Collection, it makes no difference in the game and the monitor just can't properly display the game.

Right now, I would buy an 27" IPS, G-Sync, 144HZ (or more) display with a 2K resolution rather than a 4K one.

You can change the DPI scaling of any program in Windows 10 - the latest versions are fairly good.
Create an icon on the desktop for the program (if there isn't one yet) and go to the Compatibility tab. Change the Override high DPI scaling behaviour and set Scaling performed by...

Productivity applications (at least the ones I use for development) all support 4K natively, according to the monitor size.
ie, they are perfectly readable (or to be more precise, I'd never go back to 1080p it's so much nicer) both on my 15'' 4K laptop screen and 32'' 4K desktop screen.

Only change the default scaling if the program does not scale correctly, as otherwise you apply system scaling to programs that can work natively in 4K.

Oh dear, that is clearly not ideal...
I expected things to work out better than that, with all that "4K is the future" talk. I know "legacy" applications will be hard to work out, but a 2x scaling algorithm that works well ought to be available.

Anyway, thank you for bringing this matter to our attention. I will take 4K with a bit more scepticism now.

How well 1080p stuff looks on a 4k screen really just depends on the scaling of the device. I haven't looked into monitors in a while but I bought a 4k TV around 6 months ago and some brands had excellent scaling (Samsung, Sony) while some did not (Vizio, Hicense). I would guess monitors are the same.

Unless you have $1,000+ worth of GPU power you'll likely be playing at 1080 or 1440p so it would make sense to research and get a monitor with good scaling.

I would agree with StingingVelvet, if you have the rig and the extra money. But I would not save up or splurge for it if you don't have the extra cash. Not too much has been optimized to take advantage of 4k, and some older games are unplayable because of it. I guess it depends on what you're doing too, if you're not playing anything older then a couple of years it may be worth it. For example, King Arthur Collection is completely unplayable on my laptop with a 4k monitor. There is no fix, and scaling makes the buttons giant and cover the screen. In addition, they are half off the screen and you can't press them, which makes it unplayable. If you're like me and enjoy a wide range of new and old games, you're better off with just getting a good HD monitor that doesn't have 4k.

According to Nvidia, at least their incoming new top card can manage games at 4K. Before this I saw absolutely no reason for a 4K gaming monitor but there are other uses where it is beneficial as mentioned in this thread.

I've got an Asus Predator 32". To start with I loved it, bought myself a 1080ti along with it to cope with the load, and Sniper Elite 4 was awesome to play on it.

The it started having issues with stability - found out that g-sync when not fullscreen doesn't work. My main gripe now is probably with my 1080ti, which I think overheats and has started having issues (though we were in a heatwave while I was playing shadow of war at 4K on top settings). The monitor itself is really good, brilliant image, can't fault it.

Unfortunately videos on it are not so good. Netflix looks shit now. I'm trying to watch Star Trek Beyond, but it is so bad at 4K it's nearly unwatchable. It goes at about 5 FPS, blurry as hell. I'm pretty sure it's not the film, because they made a big thing about the visuals on entering that starbase, and it was choppy and blurry. You really notice problems with visuals, and it's ultimately a really reduced experience for all films that aren't 4K.