I've definitely enjoyed having the extra screen real estate over the 27" monitor, and the extra resolution has been very helpful for having a bunch of windows open in Unity.
This year at CES there were a number of new monitors unveiled that compete in this space. There's a new Samsung monitor (G80HS) that is a 32" 6k with a higher refresh rate than what you'd find with existing offerings. Unfortunately it has the matte coating instead of glossy, so clarity will suffer.
Also of interest are the new 27" 4k offerings with true RGB stripe subpixel layout. This should fix text rendering problems, especially on Windows. Both Samsung and LG are making these OLED monitors with the true RGB layout. There will almost certainly be glossy coatings offered with these panels, and they'll have higher refresh rates than IPS. The main downside will be brightness for full screen white windows. I think the Samsung panel is a bit better than LG in terms of brightness.
This is akin to how I've (technically?) stepped back from a 5K 27" to a 4K 32". Likely due to scaling and how far I sit from the screen (about 24" -- average I think) things look the same? At least, I don't notice that the 4K is any worse.
Me being me, I can't help but think I should have a 5K or 6K or whatever, but the price is... high. So I figured I'd try a 4K 32" since the OLED was cheap and the result was this post because the subpixel pattern messed with me. But now for the replacement I'm looking at a simple (but nice color / high end) 4K 32" IPS LCD.
And having been using one for the last day, I'm pretty content with it. It's like everything I wanted from the OLED without the eye strain.
It is a really neat looking project, I just determined it wasn't for me.
The main factor is being able to sell the iMac for that relatively high price. I can't figure out why they are still so expensive because most of the early 5K models are kind of useless nowadays (on low end version, the compute just cannot cope with modern media/files at such a resolution). But maybe it's people converting them to display driving the market...
Apple excuse for stopping the big iMacs was that when you bundle up the display with the compute it makes it hard to upgrade and the whole thing become useless. But in reality it just looks like some bad "reasoning" to force people to spend more on a less elegant solution that probably won't get upgraded that much.
At least an old school 5K iMac can have some secondary use case, like you demonstrated or even just to watch movies, do some light document editing and such. And you can convert them to displays if you really want, but that should have been a built-in functionnality in the first place.
I guess this is why they still commend a relatively high-price, a good large display still has many uses even if the compute is weak.
The studio display is kinda useless outside of Mac use, so even though it's great quality its really not a good deal.
I really hope Apple finally release another big iMac because I won't get another Mac Mini or a Mac Studio. I like macOS (less so nowadays) but the whole point of the Mac was the integrated hardware for base/mid-range power. Their small desktop boxes that cannot take any upgrades are really pointless as a desktop because you end up with cable galore and not much space saved. This is so stupidly inelegant, I can feel Jobs rolling in his grave. They added front accessible ports, so that's something I guess, but come on, they stink of greed and profit maximisation at all costs...
With all that said, I would still recommend it over anything not retina.