Is the Samsung NU7100 good for gaming?

It handles console gaming at 4K, but input lag and motion are average for its generation. Serious gamers should look at sets with a game mode and higher refresh support.

Does it support Dolby Vision?

No. It supports HDR10 and HDR10+, not Dolby Vision. Dolby Vision content plays as standard HDR10.

How many HDMI ports does it have?

It has three HDMI inputs, plus USB ports for drives and accessories. That covers a console, a streaming stick and a cable box.

Is 43 inches big enough for a living room?

It suits bedrooms and small rooms with seating roughly 5 to 7 feet away. For a main living room with distant seating, a larger screen is usually better.

Does it have a headphone jack or optical audio out?

It has an optical digital audio output for soundbars and receivers. There is no headphone jack on this model.

Is it worth buying over a newer budget 4K TV?

It is a reasonable pick if the price is low and you want Samsung's app platform. Newer budget sets generally offer better HDR brightness and faster smart interfaces.