What is the difference of E-ink screen and LCD screen? Why should I choose an E-ink e-reader?

E-ink displays images and reflects light in the same way normal paper does, while an LCD display consists of lots of small light emitting crystals. LCD screens are great for general use because they are in color, and besides text it can also display videos because they have a quick refresh rate. E-ink screens are comparatively slow to refresh, so don’t display video well, and have a slight “ghosting” effect. 

Due to slow screen refresh rate of E Ink screen, all E-ink products may not be able to support well all third-party Apps or videos, which are developed for LCD/LED screens with fast screen response. E-ink is very different from LCD screen in that it’s like paper, and you read it with ambient light – including bright sunlight – rather than having a glowing screen. Therefore, the E-ink could be less eye-strain, better visibility outdoors, and lower batter consumption.