The technology used to light-up the new Kindle is more advanced than anything I've seen previously: Despite the limitation of an LED array — in this case, four tiny lights buried at the bottom of the screen — the entire screen glows with near-perfect evenness, no matter how bright or dim you set it.
What surprised me about the Paperwhite wasn't that Amazon finally cracked the lighting problem. It's that the lighting actually solves the other big e-ink problem: contrast. E-readers have long suffered the criticism that their pictures aren't really black-on-white, but black-on-gray. The reading experience falls short of greatness, no matter how "easy on the eyes" the technology is supposed to be.
By some color-temperature trickery, the Paperwhite's light system turns gray into white. Not only do you leave the light on all the time, but it is ideally kept at its brightest in all but direct sunlight (where you can't see the lighting). And speaking of direct sunlight, let me assure you that the Paperwhite retains the outdoor virtue of e-ink despite the lighting system and the capacitive touch sensor layer.
Also, The Digital reader blog has a whole bunch of links, from Engadget, to TIME: