Which is better for a bright living room?

The Hisense U8N. Its Mini-LED backlight reaches far higher brightness and its anti-glare coating handles daylight and lamps better. The LG C6 wins in a dim room where its perfect blacks show.

Which is better for gaming?

The Hisense U8N has the edge on paper with 144Hz, VRR from 48 to 144Hz and 6.1ms input lag. The LG C6 is close with 120Hz, VRR and a 0.1ms response, and many players prefer OLED motion clarity.

Both should run for years. OLED pixels dim gradually and can burn in with static logos or news tickers; LG's OLED Care helps limit that. Mini-LED backlights avoid burn-in but can develop uneven dimming over time.

Is the LG C6 worth stepping up to over the Hisense U8N?

If you care about contrast, viewing angles and motion, yes. If you need a very large screen or watch mostly in daylight, the Hisense U8N is the more practical pick.

Which has better sound?

The Hisense U8N has a 2.1.2 five-speaker, 50W setup with surround processing. The LG C6 uses a 2.2 channel system with Dolby Atmos. Both benefit from a soundbar.

Do both support Dolby Vision?

The LG C6 supports Dolby Vision, HDR10 and HLG. The Hisense U8N supports HDR10 and Dolby Vision on most sizes; check the specific size you buy.

LG OLED C6 65-inch TV vs Hisense U8N Mini-LED QLED TV

Buy the LG C6 if picture quality in a dark room and gaming response matter most. Its OLED panel gives per-pixel blacks, near-instant response and wide viewing angles, and owners rate it highly. Buy the Hisense U8N if you watch in a bright room or want a big screen. Its Mini-LED backlight hits far higher brightness and comes in sizes well past 65 inches, but blacks and off-angle viewing are weaker than OLED.

Choose the LG C6 if you want perfect blacks, wide viewing angles and the fastest response for movies and gaming in a dim room.
Choose the Hisense U8N if you watch in a bright room or want a screen larger than 65 inches with high brightness for HDR.

Prices

LG OLED C6 65-inch TV: $899.99 at Amazon (last seen Nov 12)
Hisense U8N Mini-LED QLED TV: $997.96 at Amazon (checked today)
Difference: the LG OLED C6 65-inch TV is $97.97 cheaper than the Hisense U8N Mini-LED QLED TV at the latest prices (Nov 12 and Nov 14)