Value Rating: Includes price and our assessment of what you get for your money. There are some very pricey eReaders out there which aren't good value, and cheap ones which don't deliver.
Features Rating: Includes the eReader's capabilities, display quality, wireless connection, formats, ease of file transfer, etc..
Usability Rating: How fun and easy it is to use, how often it crashes or how badly buttons are designed. This is the most subjective of the measures, generated from our testing experience as well as user comments from across the net and blogosphere.
Screen Size / Greyscales: The personal eBook reader size is fairly standard at 6 inches diagonal, or 600x800 pixels as many judge this an ideal paperback-type size for casual, one-handed reading. Bigger isn't necessarily better. The number of greyscales is important if you'll be displaying pictures; early readers did 4, recent ones do 8, and the best models do 16.
Connectivity: Most eReaders use a USB 2.0 cable to connect and charge to a computer, but a few have WiFi/Bluetooth and only the Kindle 2 has a cellular 3G data connection allowing wireless ebook downloads and basic web surfing.
Memory: This is built-in memory that comes with the eReader out of the box. Most readers allow you to add more memory via various slots.
Battery life: Most eBook readers list this in page turns/refreshes, as maintaining an e-ink display "on" draws no power, but when you add functions like wireless, touchscreen, etc., battery life diminishes rapidly, so consider estimates rough.
Weight: eReaders currently weigh surprisingly little, usually less than a paperback.
Audio: Nearly all eBook readers have a headphone slot, and some even have speakers.good if you like background music.
Input Device: These vary from physical keyboard, to touchscreen to D-pads.
Screen Refresh: How long it takes to refresh the entire e-ink screen.
File formats supported: The number of format types the eReader supports. This is perhaps not a very useful metric, as if you only use PDFs and MOBI files for instance, it doesn't matter how many more are supported. See eBook reader Basics for if you require more detailed info.
Release date : When the current model was released--useful as it gives an indication. Newer is usually better, but some older models like the Sony PRS-505 remain a good value favorite with high specs.
Notes: Some prominent notes on distinguishing features--see detailed review pages for more.
Price: These are prices in dollars for the US market. As we try to list all major eBook readers worldwide, and not all are released in all markets, so we have tables for US eReaders, UK eReaders, European eReaders, and Asian eReaders priced in local currencies and with local buying options.
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eBook Reader Basics