Screen type
Did you know that electronic book readers much meant E-ink? Well, the planned arrival of the Apple ipad tablet as the viable eReading device has now since changed that.
When picking an e-reader, ask yourself if you don’t mind reading books while on an LCD screen or prefer the more paperlike look of something such as E-Ink. Each has advantages and disadvantages. E-Ink tends to lessen eye strain and greatly improve battery life. An LCD screen can display color and typically includes touchscreen capabilities also. Then you have hybrid readers much like the Barnes & Noble Nook and Spring Design Alex, which feature both an electronic LCD screen and a paper display at the same time.
For electronic paper displays, ensure you compare touch screens as some have greater contrast than others.
Dimensions
Fortunately, you will find all kinds of options in existence with regards to size. Sony’s Reader Pocket, for example, actually fits in my jeans pocket, however its 5-inch screen still is large enough for comfortable reading. It’s also pretty light-weight and is very easy to tote around while on the road. In the middle of your selection, you have devices like the Spring Design Alex, Sony Reader Touch and Reader Pocket,
Amazon Kindle, and Barnes & Noble Nook. Then you’ve got the large devices, such as the Apple Ipad and Kindle Dx, which have screens which are about ten inches in length. Unless you’re a kangaroo, you ain’t fitting those in your pocket anytime soon. But they’re very good if you’d prefer a screen with larger display screen.
Interface
Controls for electronic book devices are typically determined by either buttons, touch-screens or a mixture of both. Button-based controls require less power and are generally more accurate but can also be more hard to use. Touch screens are usually more intuitive but could be laggy, smudge-prone, and typically draw more juice from your battery.
Button-based devices include Amazon’s Kindle Dx, 1,2 and 3 models, plus Sony’s Reader Pocket and the Kobo eReader. The Nook and iPad are almost completely touch-based. The Sony Reader and Spring Design’s reader both use touch and button controls.
Life of The Battery
According to whether you’ve planned to just read primarily at home or on the road, your battery life is an important consideration. Basic eReaders without fancy whistles and bells typically have longer battery life that’s measured in “page-turns”. Sony’s ereader sports 7500 page turns while the Kobo boasts as much as 8000 page turns. Devices with Web browsing and WiFi alternatively, tend to have reduced battery life. Spring Design’s Alex, as an example, lasts pretty long between charges when primarily using it’s E-Ink display but loses energy faster when browsing or watching videos on its LCD screen.
Features
Some devices – just like the Reader Pocket and Kobo Reader – are designed purely for reading and skip on extra features, including music playback. The Nook, on the other hand, plays tunes, has Web browsing, and 
even throws in an amazing touchscreen interface. The Alex boasts those traits plus video playback, and the ability to download Android applications. At the high end of the features spectrum is the Ipad Tablet, which happens to be much like a miniature computer.
Capacity
This determines exactly how much media/data you could squeeze into your device at one time. The larger the memory, the more eBooks and files you can easily fit in. High capacity is primarily important for multimedia eReaders that can also use apps, play music and videos. Apart from storage space, some devices also come with a external slot with an SDcard, that permits your ebook to typically increase your capacity to as much as 32 gigabytes.
Store Access
Dependent upon the device, an eReader can have immediate access to specific eBook stores, this means extra convenience, a wider selection, along with the opportunity to easily obtain the latest best-sellers. The Kindle, by way of example, has direct access to Amazon’s online bookstore whilst the Nook and Kobo’s have access to Barnes & Noble and Borders respectively. Devices that don’t have direct store access can continue to display compatible eBooks but you’ll be required to download them from your laptop or computer first.
Price
Ultimately, this really is the biggest factor when determining to buy a book reader. Since of course, your wallet virtually dictates whatever you can or can’t buy. Although many analysts and industry insiders declare that $99 is the magic price point for wide-range eReader acceptance, the current market has not quite reached that period yet as a whole. But it is 10x better that it was, say, in early 2010, after you had more ereaders sporting price tags past four hundred dollars.
You can pretty much get a good eReader from $150 to $200, that also includes basic readers such as Reader Pocket and Kobo, a tweener similar to the Kindle, plus some more feature-filled devices including the Nook and Reader Touch. During the higher end with prices of three hundred dollars and higher (sometimes a lot higher) would be the Kindle Dx, Spring Design Alex, and Reader Daily.