That I don't actually know. A cursory Google search seems to indicate that they're effectively LEDs capable of transmitting a "purer" level of RGB lighting in relation to black levels (so on screen black will actually look black). I don't recall seeing one in person, so that's about as far as my...
Definitely OLED. The colors are more vibrant and the screen just looks better under direct sunlight. Unfortunately, I don't like it so much that I'm willing to pay an exuberant price for an OLED television or Switch. And since OLED was mentioned, it's worth bringing up this meme again. :eyes: