Which is better for a bright living room?

The Samsung S90F. Its anti-glare coating and smaller panel cope better with daylight and window reflections. The LG C6 is at its best in a darker room.

Which is better for gaming?

The LG C6, on refresh rate: 165Hz against 100Hz gives smoother motion in fast games. The Samsung counters with four HDMI ports, so more consoles and a soundbar can stay connected.

Is the LG C6 worth stepping up to over the Samsung?

If you have the wall space and sit several feet back, yes. The 65-inch panel and Dolby Atmos make it the more cinematic set. In a small or bright room, the 48-inch Samsung is the more practical choice.

Which has better sound?

The LG C6, which lists Dolby Atmos surround formats. The Samsung relies on standard TV audio, so a soundbar helps either set.

Both are OLED panels from established makers, and neither has a published lifespan edge. OLED brightness fades gradually over years of heavy use; the LG's higher refresh and larger panel matter more day to day than longevity.

Do both support streaming apps?

Yes. The Samsung runs Tizen with Netflix, YouTube and Disney+, and the LG runs webOS with the same major services.

Samsung S90F 48-Inch OLED TV vs LG C6 OLED 65-Inch TV

The LG C6 is the better TV for most people: a 65-inch OLED with 165Hz refresh, Dolby Atmos and webOS is a bigger, smoother, more cinematic set than the 48-inch Samsung. The Samsung S90F wins on size for small rooms, glare handling and connectivity, with four HDMI ports against two. Owners of both lines praise OLED contrast and deep blacks; the Samsung's anti-glare coating suits bright rooms, while the LG's larger panel and higher refresh suit dark-room movie and gaming setups.

Choose the Samsung S90F if your room is small or bright, you sit close, or you need four HDMI inputs and anti-glare.
Choose the LG C6 if you want the biggest OLED picture for a main room, smooth 165Hz motion and Dolby Atmos sound.

Prices

LG C6 OLED 65-Inch TV: $1,399.99 at Best Buy (checked today)