It actually runs pretty cool - 27C all over vs 35C (bottom) to 45C (top) with a 30". When I had four 30" (500W), I would cook on warm days! Basically this uses about the same power as a 30" but with twice the pixels.
One good thing is that it is not very reflective, only being noticeable on dark backgrounds, and then not much, as can be seen from how little of the flash can be seen. On the other hand, the touchscreens are too reflective. I used to have them together on the desk when it faced the studio to the left of the picture, and one of them would reflect the ceiling light so that it was very difficult to work with. The picture shows them with reflections of the main screen, but at the sitting position, it fortunately can’t be seen in them.
And watching upscaled BluRays from just over a metre away is great.
I suspect that their 48" (48HU8500) 4K TVs will be big amongst computer people wanting to converge their TV and monitor to save space.