I'll be using the same monitors I'm using with my Mac Pro:
• a Lenovo S28U-10 (UHD, 27", bright, made for business-folk rather than graphic artists but punches above its weight and has very minimal bezels. It appears to be $265 on Amazon at the moment, though I think it might be a discontinued product.) Text and graphics look very retina-y on it, I doubt I could tell the difference between 4k and 5k with my eyes more than a few inches from the display.
• a QNIX QX2710 (27", 2560x1440, cost $214 back in 2016 and was the same LG panel everyone was using). This one's bezel is very ugly and it's slow to switch inputs and has an annoying menu system, I might replace it with another Lenovo S28U when it dies. Or maybe I'll give one of those super-wide displays a try.
I calibrate 'em with an i1DisplayPro, but for checking color and evaluating outputs I've got a Flanders Scientific.
The Studio Display looks like a very nice product but doesn't look like a great value proposition for me.
• I work in sRGB/rec.709 and verify imagery on a reference monitor and trust in scopes/waveforms so don't need P3. In fact it can sometimes be more difficult to calibrate a wide gamut monitor to accurately represent rec.709 unless you shell out for a spectrophotometer rather than a more-affordable colorimeter. Apple's got a history of shipping monitors with better than average pre-calibration so that might not be an issue.
• I already have 5.1 in my office so have no need for a monitor with tiny built-in speakers (though reportedly they sound good for their size).
• I use my laptop for zoom so don't need a webcam built into a display. Half the time on work calls I turn my video off.
As nice as 5k sounds, 4k for 1/6 the price works for me.
I mention all this not to criticize the idea of purchasing Apple's new display -- it does look beautiful and minimal and I think those who buy it will enjoy sitting down to work in front of it. If money was no object I'd get two. But if a $1500+ monitor sounds like a lot to you, don't fret. You can compromise for a lot less and get something functionally equivalent in all the ways that likely matter for your work.
If I come to regret not buying the Studio Display, I figure I can always save up and buy one next year.