It's not terrible, but it's nowhere near as nice as the 27" 5K.
But even on Windows, the choices at 27" 4K aren't great. 100% is too small. 200% is too large. 150% is quite nice, but I find apps regularly don't scale properly, and text still isn't as nice as 200% on a 5K display.
edit: and on Linux, it's similarly not great - integer scaling works quite well on most modern DEs. Fractional scaling is a mixed bag and a lot of apps have broken or compromised UI when it's in use.
As an aside, a user here recommended putting the outside monitors in vertical mode with the middle monitor in horizontal mode. It works extremely well for reading websites/documentation/terminal output while coding in the middle panel.
I think it could make a great secondary though.
I use 1.5× scaling in Sway, and haven’t observed even the slightest problem in any Wayland app. (I also use the high-DPI patches for XWayland, and run it at 3×, so that it’s an integer multiple of my scaling factor, a minor visual improvement on the very few X11 things I use that is probably not worth it.) I will note, however, that Firefox is rendering content at 2× and downscaling; setting the experimental widget.wayland.fractional_buffer_scale to 1.5 distinctly improves rendering, but had some very annoying bugs when I tried it several months ago which became debilitating maybe a couple of months ago, so I gave up on it.
Led to some pretty broken looking UI.
(One thing that is comically broken about Sway and I think Wayland in general is cursor sizes. Specifying `seat seat0 xcursor_theme Adwaita 96` nets me at least four or I think five different cursor sizes, varying by app, and at least one of the dodgy sizes is actually a fractional scaling bug, scaling by ceil(1.5) rather than 1.5.)
There's always a balance and trade-off here.
2x scaling with 4k really means you end up with the same screen real estate as 1080p.
In my opinion I would very much prefer 24" or 25" at 1440p with native scaling which is ~120 PPI. I personally run both a 25" 1440p display and another 24" 1440p display at 1x. I still consider going from 1080p to 1440p one of the biggest quality of life upgrades I've encountered when I made the switch 7 years ago. It's the same level of "wow this is great" as going from a HDD to SSD.
Before there were shortages you could get a high quality IPS panel monitor from a reputable brand (Dell, ViewSonic) with low input latency for around $300. 4k at 1.5x also gives you the same real estate as 1440p but with higher PPI but I don't know how crisp that will be given the scaling ratio.
Yes and no. With much clearer looking text, I can use smaller fonts (13 -> 11 in IntelliJ) than on regular 1080p displays, so there's _some_ difference.
Is that even a problem? I am not buying better screen to torture my eyes. IMO. A smaller sharper text won't really be easier to see compared to a larger but blurrer text.
I wear glasses and 25" at 1440p has very clear text. I feel no strain. Even the grey text on HN is very readable from about 32" (81 cm) away which is my normal viewing distance. It's readable without much strain from 45" (114 cm) but I wouldn't want to use things that far away.
For reference my work issued laptop is a 13" 2020 MBP so I have experienced retina. I would take the 1440p screen real estate at ~120 PPI (24"/25") 10 out of 10 times vs going back to 1080p but with higher PPI. There's also the added benefit of never having to think or worry about poor UI scaling since not all apps handle scaling well, but that's not a deciding factor in my mind, more of a nice to have.
I never need to run app and editor side by side on same screen. I always have 2+ screen in any setup. So I just threw it to another if I want ever want to run it side by side. And besides, I seldom codes with my 27 4K screens.
They ares used mostly on browsing web/gaming. which you can't use something side by side isn't even a issue.
1.5x is nice on a 27 inch 4k with 14+ fonts. HiDPI monitors do seem to have bloom, so slightly bigger fonts with higher DPI are good to have.
In terms of viewing space this fits (4) side by side code windows at 80 characters with a little bit of breathing room.
For screen size, I think there is some screen size that's most comfortable to view, and I want to say that's like ~40% of the human FOV... so, I think a 24" monitor and 15" laptop are most comfortable for me, but 27" might be a bit nicer if you're using it for media as well.
I believe that depends entirely on the desktop environment. Sway does real fractional scaling rather than the idiotic downscaling way.
Of course, independent of the desktop environment, you could just tell supporting applications to just manually render bigger UI (exactly how you would on X11 with some TOOLKIT_DPI variable thing per UI toolkit) and keep the monitor scale in the compositor at 1x. That's probably what you've been doing. That doesn't support multiple monitors with varying scale.