Whether you prefer a curved or flat screen is primarily subjective, but the slightly curved screen does provide several important objective advantages:
First and foremost, the concave screen shape cuts down on reflections from surrounding ambient light two ways: by reducing the screen’s 180 degree opening angle, which eliminates reflections from some ambient lighting on the sides, and also from specular (mirror) reflections off the concave screen, which directs some reflected ambient light from behind the viewers away from their line of sight. This is very important for a display technology that produces excellent dark image content and perfect blacks – because you don’t want that spoiled by ambient light reflected off the screen.
The slight curvature reduces visual geometric distortion: When you watch a perfectly flat TV screen, the corners of the screen are further away than the center so they appear smaller. As a result, the eye doesn’t see the screen as a perfect rectangle – it actually sees dual elongated trapezoids, which is keystone geometric distortion. The slight curvature on the LG OLED TV reduces this subtle keystone geometric distortion by 50 percent at a typical 8 foot (2.4 meter) viewing distance.
The slight curvature improves viewing from the sides away from the central sweet spot: A second and more subtle point: people sitting off to the sides away from the central sweet spot actually get a somewhat better viewing experience than with a flat screen because the curved screen accommodates their viewing direction better by compensating for some of the uneven image foreshortening that is seen with a flat screen: the image on the side of the screen closest to you appears larger, and the image on the side of the screen furthest away appears smaller. The inward curvature of the screen compresses the foreshortening of the image on the near side that appears larger, and the curvature on the far side enlarges the distant part of image that appears smaller, which improves the overall screen image geometry that is seen away from the central sweet spot.
The flip side is that the top and bottom of the screen and picture don’t look perfectly straight, but rather appear with a slight subtle curve – it’s a small geometric effect, only a 1.5% curve (difference between the center and sides) is seen at an 8 foot (2.4 meter) viewing distance. It’s more apparent when the room lights are on, but much less so in low ambient lighting, which is the best way to watch the TV. I found that if I didn’t make a point of looking for the slight curvature, I didn’t notice it. For me, the advantages of reduced reflections and better side viewing outweigh noticing a slight curvature, but it is none-the-less still a subjective call…
It is important to emphasize that the curvature is subtle, just 1.4 inches (3.6 cm) on a 55 inch (1.4 meter) screen. That is just the right amount to significantly improve the picture quality as described above. Reviewers who have said the opposite, that the curvature interferes with multiple viewers or viewing away from the central sweet spot have clearly not spent much (or any) time actually viewing (and testing) this curved screen TV.