I've been using a Samsung 40" 4k TV as my main monitor for development work for about 8 months and it's been great for me.
A couple caveats -- Because I don't game or do graphics work, I don't know or care about color reproduction. I made sure to get a TV, graphics card, and cable that supported 4k@60hz with 4:4:4 chroma so the text is perfectly sharp and the refresh is not obtrusive. It's not hard to find a Samsung TV around $350 that supports that, but as far as I could tell, I had to go up to a GTX1050 graphics card to get that. I sit between 24 and 28" away from the monitor so the text is readable to me at full resolution. At that distance, I do have to turn my head to comfortably read text in the corners of the TV, especially the upper corners. In practice, that means I keep monitoring-type applications such as CPU charts, Datadog graphs, etc., in one of those corners for quick reference. While I still have two 1920x1080 monitors on either side of the TV, it's quite nice to be able to open up on my main monitor a huge IDE window and, when necessary, put 3-4 normal-sized windows next to each other for comparison work.
Same here. I bought a Philips BDM4065UC monitor in 2015 (40 inch, 3840x2160 resolution) for 740 € (in Germany) and I'm loving it. The only cave-at with that model is that reaction time is a bit slow (I would guess 5 ms between full black and full white).
When I replace it, the replacement will be the same size and resolution, but I'll probably go for OLED and HDR-10 or better.
I happened to buy the same, and import it from Germany to the UK.
Was very excited for it as it featured a very similar DPI to a 27" 1440p Korean import, coming from 3+ 1080p monitors originally the lack of bezels was incredible.
It's not built for gaming at all though, extreme screen tearing and poor response times has me now looking to replace the 27" 1440p Korean import with something >144Hz and G-Sync, before replacing the Philips BDM40.
Yeah, I got that Philips too. For games 40 inch at 4K resolution is really a lot more practical then 38 inch with an odd resolution, and it's cheaper too.
I think the fact that the 27" monitors next to it are closer to the camera in that photo makes the TV look artificially smaller. It absolutely dwarfs the 27" monitors. If you're close to any store that carries 40" 4k TVs, though, just go there and stand 28" away from one. I think you'll see what I'm saying about having to turn your head to comfortably read text in the corners, something that has never been the case for me with smaller monitors.
I just bought (today) a 32" 1080p monitor and I'm lovin' it.
I think it's more productive to use a single big screen then set up a two monitor setup.
My old setup consisted of two monitors, one 23" and one 21". One day I realized that my 23" monitor could not reproduce colors. I needed to photoshop a picture. I sent the retouched version to my phone, but as I couldn't see the color depth on the 23" one, the image looked ugly on the better screen. At that time I learnt not to buy the cheapest monitor, just by looking at its size and resolution. So, I sold that monitor, and bought a 32" 1080p monitor at a bargain price.
Of course it would be better if I could buy a 1440p monitor at this size, (or even 4K OMG :)). But considering my budget this was all I could purchase.
I had serious doubts about the pixel density, however there was nothing to be afraid of. In usual tasks (e.g. browsing, writing code in emacs, terminal) nothing disturbs my eye, it's beautiful. However, if I open a 1080p youtube video fullscreen, it looks like as if it were a high quality SD video, because of the pixel density. I am standing close to the monitor, and although I cannot see any pixel points, I can notice the difference.
I bought my monitor for 900 Turkish Lira, equivalant to 254 dollars and I think it is a great investment.
I detect no lag when moving windows around. It might not (or might -- I simply don't know) be good enough for gamers, but it's definitely smooth enough for development, document, or web browsing (aka productivity) tasks.
144Hz monitors do produce a very noticeable difference for gaming if you can rival the refresh rate with in-game FPS, outside of gaming I've only found it noticeable when moving windows about.
For productivity I'd go for the 40" 2160p over a lower resolution higher refresh panel.
Mine is a 40" Samsung UN40KU6300 though Samsung appears to rev its model lineup frequently so they may have already released a successor to this model. It was a little difficult to confirm that it supported 4k@60hz with 4:4:4 chroma, but I relied on the experiences of some folks on an audio/video forum who confirmed that they had been able to run with those settings. Unfortunately, I don't remember the name of the forum or have it in my browsing history. I do wish manufacturers would make that information easier to come by though it's certainly a tiny minority of consumers that know or care about those kinds of specs.
rtings.com is a TV review site that is superb for finding such details, they test for 4:4:4 chroma specifically along with input lag in each mode and one of their sub-cores is "use as a PC monitor". A valuable resource.
A couple caveats -- Because I don't game or do graphics work, I don't know or care about color reproduction. I made sure to get a TV, graphics card, and cable that supported 4k@60hz with 4:4:4 chroma so the text is perfectly sharp and the refresh is not obtrusive. It's not hard to find a Samsung TV around $350 that supports that, but as far as I could tell, I had to go up to a GTX1050 graphics card to get that. I sit between 24 and 28" away from the monitor so the text is readable to me at full resolution. At that distance, I do have to turn my head to comfortably read text in the corners of the TV, especially the upper corners. In practice, that means I keep monitoring-type applications such as CPU charts, Datadog graphs, etc., in one of those corners for quick reference. While I still have two 1920x1080 monitors on either side of the TV, it's quite nice to be able to open up on my main monitor a huge IDE window and, when necessary, put 3-4 normal-sized windows next to each other for comparison work.