All models of the Kindle come with the basic interface and "e-Ink" display technology that sets this line of electronic readers apart from others on the market. Three editions of the Kindle are available at the time of publication: the Kindle Wi-Fi, the Kindle 3G + Wi-Fi and the Kindle DX. A fourth model -- an advertising-supported edition -- is slated for release in May 2011. Choosing the model that's right for you will depend on how you intend to use the Kindle and what experience you'll find most enjoyable.
Compare the size and weight of each device. The Kindle DX offers a larger screen, measuring 9.7 inches, compared to the 6-inch screens on the Wi-Fi and 3G + Wi-Fi models. The DX model has a smaller keyboard than the others do, although the overall device is significantly larger and 284gr heavier.
Determine your budget for a new e-reader. The ad-supported Kindle is the least expensive with an expected price tag of £74 at the time of publication; the Kindle Wi-Fi is £90, the 3G + Wi-Fi is £122 and the top-of-the-line Kindle DX is £246.
Decide how you will connect your Kindle to the Internet. No matter what version of the Kindle you choose, you'll be able to connect to the Internet wirelessly. If you plan to be away from your Wi-Fi connection or do not have a home wireless network, choosing the 3G + Wi-Fi model may be better suited to your needs. The 3G service does not require a monthly plan and allows you to download files and even access the Web using the Kindle's experimental browser.
Consider whether you are willing to view advertising on your Kindle. The Kindle Wi-Fi with Special Offers carries a lower price tag, with a trade-off of advertising and commercial screensavers. Whether or not the intermingling of advertisements with your e-books is worth the discount depends entirely on your preferences.
Compare the expected battery life of each model. The Kindle DX offers a battery life of two to three weeks with the wireless turned off and one week when Wi-Fi is enabled. Other Kindles can last up to one month on a single charge with the wireless disabled. With wireless turned on, the Kindle Wi-Fi can last up to three weeks and the Kindle 3G + Wi-Fi can last 10 days.