The Samsung QN800A is great for most uses. It's an excellent choice for use in bright rooms, like when you're watching shows or sports, because it gets bright enough to combat glare and has fantastic reflection handling. It has great gaming features like VRR technology and HDMI 2.1 support. It also has very low input lag and an excellent response time. However, it struggles in dark rooms due to its low contrast ratio and poor local dimming feature that causes blooming around bright objects. It also doesn't display a wide color gamut for HDR content, but has fantastic brightness.
The Samsung QN800A is good for watching movies. It has a VA panel with a decent contrast ratio that’s lower than most VA panel TVs, causing blacks to look gray. Its full-array local dimming feature does a good job at improving the contrast for deep blacks, but it causes a ton of blooming. Luckily, the TV upscales lower-resolution content, like from Blu-rays, without many issues.