Which is better for a bright living room?

The Samsung S95F. Its Glare Free coating and brighter OLED HDR Pro panel hold up much better against windows and lamps. The LG C6 is a standard OLED with no anti-glare treatment, so reflections are more visible in daylight.

Which is better for gaming?

The Samsung S95F. It has four HDMI inputs, VRR up to 4K 165Hz and Motion Xcelerator, so a console, PC and soundbar can all stay connected. The LG C6 also runs at 165Hz but gives you only two HDMI ports.

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

If distance and immersion matter most, yes. A 77-inch screen is noticeably more cinematic from across a room, and both are OLED. If your room is bright or you need ports and sound, the 65-inch Samsung is the stronger all-round set.

Which has better built-in sound?

The Samsung S95F. Its 70W 4.2.2-channel system with top speakers and Object Tracking Sound+ is well ahead of the LG C6's standard array. Neither replaces a dedicated soundbar for deep bass.

Do both support Dolby Atmos?

Yes. Both decode Dolby Atmos, though the Samsung's speaker layout makes more use of it. The LG passes Atmos through to a receiver or soundbar over HDMI.

Both are OLED panels with similar lifespans under normal use. The Samsung's anti-glare coating and higher brightness are the bigger practical differences; burn-in risk is low on either unless you leave static logos on for hours daily.

LG C6 OLED 77-Inch TV vs Samsung S95F OLED 4K TV

These are two OLED TVs at very different sizes. The LG C6 is a 77-inch panel, so it wins on sheer immersion and is the pick for a large, dark living room or home theater. The Samsung S95F is a 65-inch set with a brighter, glare-free coating, four HDMI ports and stronger built-in sound, which makes it the better fit for a bright room or a heavy gamer. Both use OLED, so contrast and black levels are excellent on either; the real split is size versus brightness, ports and anti-glare.

Choose the LG C6 if you sit far from the screen, want the biggest picture your room allows, and mostly watch in a dim or dark room.
Choose the Samsung S95F if your room gets daylight, you own several consoles and soundbars, or you want a brighter picture and better built-in audio.

Prices

LG C6 OLED 77-Inch TV: $2,279.99 at Best Buy (checked today)