Ok so here's my thoughts after several hours!
Firstly, the colours out of box vs calibrated, I found the Creator mode set to sRGB to be the most eye pleasing and natural "feeling" to my eyes. But running DisplayCAL on this mode showed that it was slightly off from 6500K when the luminance even after setting the brightness to my target preference:
So I set it to Game mode and custom colour from within where you can then adjust RGB and ran a calibration session which resulted in
this result which I am very happy with. Even after this result, the look of everyhting on screen appears different to the IPS panel and matte coating I've been used to for since basically forever. This will take some adjusting. It's mostly due to black and dark colours being so rich and pure, and the coating on the panel is glossy so light and blacks aren't diffused. I have no issues with reflections either, I find one of my Hue light orbs behind me at the far end of the room is now no longer a distraction as the white light isn't being diffused by a matte surface coating like on the LG so I'd normally have it off when working at the desk. Now it's a subtle AR controlled reflection that has a reddish tint to it, much like how a watch AR coating on top does on reflections. I like this.
The Gsync fan noise, it does ramp up from time to time I have found, though infrequent. Here is a video showing what it sounds like:
^Recorded on my phone which has good mics but you may want to up your volume to hear it best. This is more audible than my PC as mentioned but I appreciate that my PC is quieter than most laptops out there so this is to be expected I guess although you will be able to hear the fan as an ambient hum in any moderately quiet room. the noise does not really distract from watching content etc though.
Panel uniformity, stuck pixels etc... No issue to report. It feels like it weighs less than my old LG 34UM95-P, even though they are similar on paper. The LG had a solid metal frame, this is all plastic fantastic aside from the front panel.
I like the way the cables are tucked in the back and have routing so that they exit through the middle through one area. Tidy. This is even before you install the back cover if you choose to do so.
I REALLY like the VESA 100x100 mounting bracket., makes using this on an arm a total breeze. Essentially attach bracket to the arm plate, then slot the monitor on the bracket. Classic Dell mounting system which I am fond of but they never had a separate bracket like this in the past with monitors, you instead had to screw the arm directly onto the monitor after detaching the stock stand. This system also means if I ever need to make use of the 3yr warranty and get it swapped out, then it's a simple case of unplugging 3 cables from the back, then pressing the eject button for the bracket.
I like 144Hz scrolling (am in 10bit but working in sRGB/SDR only), things are so smooth and fluid
Some photos, some of these were with the DSLR before I packed it away and used the phone, just incase anyone wonders why there's a PQ difference
And some quick Cyberpunk 2077, Gsync Ultimate is pretty sweet, kept vsync off and let the module do its thing, no max fps set in game any more as on the 60Hz monitor it had to be capped at 60 to keep things smooth, now all limits are off and it's just so smooth and instant, especially the fact that it's max RTX lol.