One of my friend lately gave me Kindle 4 just for a few days. Wow man I'm amazed by it. Here is my review.
The only downside is its refresh rate is very low. Even with this downside I'm loving it to the core.
The display
The stunning e-ink display(480x800 px I guess) is crisp even though it's only a grey scale black and white display. Perfect for book reading! The background white is almost like paper. No stress on eyes what so ever, even in bright sunlight. Unlike the LCD/AMOLED displays which consume the bulk of the power, e-ink takes very low power. On top it these displays do not need power once the page is drawn on screen. Even if the display module is disconnected it continues to display last drawn image.The only downside is its refresh rate is very low. Even with this downside I'm loving it to the core.
The battery
Kindle has an amazing one month battery life if you read it for half an hour to one hour daily. If you use it more often I would say battery life is still good and depends completely on number of page turns and dictionary lookups. If WIFI is turned on the battery life would come down drastically to may be 1 week, so make sure that you keep it in airplane mode when WIFI is not being used.
The browser
Kindle ships with experimental browser support, even though there is nothing great about it, it is nice to have feature.
