I'm a gamer. So when I look at a monitor, the first things I look at are the refresh rate and response time. For some folks, those qualities are all but immaterial. Photo pros and graphic designers need consistent, accurate color and brightness, along with a super-wide color gamut. For that kind of workload, you need something like Viewsonic's VP2785-4K. This is a 27" IPS monitor with a resolution of 3840x2160 that utilizes a 10-bit IPS panel and a 14-bit look-up table to achieve 96% coverage of the DCI-P3 color space.
4K resolution means that users get a lot of pixels to move windows around, and 27" should be large enough that most people shouldn't need to employ display scaling. The VP2785-4K also has a maximum brightness of 350 cd/m², although most professional users will keep the display well below that level to preserve the correct gamma. As it uses an IPS panel, the monitor has 178º viewing angles both horizontally and vertically.
ViewSonic list the display's typical response time as 14 ms. That can be dropped to around 7 ms by enabling overdrive, though monitors like this are typically used without the feature enabled in order to avoid the visual artifacts it can cause. Curiously, the company lists this display's vertical refresh rate as ranging from 24 Hz to 120 Hz. It's possible the monitor could ramp up the refresh rate in lower resolutions.
The VP2785-4K comes factory-calibrated with a guaranteed Delta E value of less than 2. There's also a built-in calibration feature in case the display's environment changes. An LCD's temperature can affect its color presentation, so the company says that it engineered the VP2785-4K to warm up and stabilize in just 3 minutes. Viewsonic also baked in HDR10 support for good measure.
Image-editing professionals can hook up to the VP2785-4K using HDMI 2.0, DisplayPort, mini-DisplayPort, and USB Type-C with DisplayPort Alternate Mode. That makes it ready to hook up to just about any modern machine, including recent Macs. Viewsonic offers a three-year warranty. If this is just the display you've been looking for, head on over to Amazon where you can already order it for just a bit over its $1200 list price.