Sunlight readability is an interesting difference between computer display technologies. Displays based on the very mature reflective and transflective, (mostly monochromatic and passive matrix) FSTN/DSTN LCD gain readibility with increased exposure to sunlight. In essence, that means you can both read electronic books and take notes outside in nature, be it under a tree, or just seated in the park. The displays that are dominating the (initially only portable) market for more than a decade now is the transmissive (active matrix) TN TFT/LCD. These displays, on the other hand, loose readability with exposure, and are best viewed indoors, or in deep shade. Naturally, the level of usability varies with both season, and the exact model of display. They also manufacture ones that are equipped with very powerful backlights, but you must keep in mind the possible effects on both your batteries, and on your eyes.