The Samsung S90D/S90DD OLED is mostly better than the LG C4 OLED. The Samsung gets brighter in HDR, so bright highlights stand out more on it, and it maintains its HDR brightness better while in 'Game Mode.' The Samsung TV also has a wider color gamut, better color volume, and better HDR gradient handling, so colors in HDR are more vibrant, lifelike, brighter, and have less banding. The Samsung has a wider viewing angle, and the image doesn't have a green tint that worsens as you move off-center, so it's the better choice for watching TV in a group setting. However, the LG supports Dolby Vision and DTS audio formats, so it's the better option for those looking to get the most out of their physical media.