The screen is much bigger in Cinera but really much closer to the eyes too. And this very short distance make me feel less comfortable than the Sony experience, especially with fast movements ! With quite scenes it's OK.
octiny I don't have a 4K player, so I can't give my impression on that subject.
I tested the burden free arm, and it's very convenient and comfortable, a good point in comparison with Sony.
Finally, I watched parts of Life of Pi movie. 3D is really good, but contrasts are less impressive than on Sony OLED screens (night scene with the whale).
I think that due to LCD, my eyes were tired after half and your watching, whereas on Sony I can watch 2 hours without eyes problems (but with headache due to the weight !!).
I also really miss dioptric correction, there is enough room for glasses, but it would be great if I could remove them during the movie !
Tomorrow I will try it with Black Panther which has very good 3D effects.