Apple's iPad vs. e-readers

Apple's iPad tablet: Also an e-reader

Apple's iPad is a multi-function device that focuses on multimedia and some productivity apps, but also functions as an e-reader with a new iBook store of EPub format books. Five major book publishers, plus The New York Times, have all signed on to give users views of their content from the iPad's 9.7-inch color, multi-touch screen.

It might seem inappropriate to compare this 1.5-pound device with some much lighter-weight e-readers that have far superior battery life than the 10 hours Apple claims for iPad (and probably only when not connected to Wi-Fi or 3G wireless). A big question is whether iPad's LCD screen, with its LED backlight, will only work for casual readers who also browse, play music and videos and write documents, and not for heavy readers.

Those who like to read several hours at a time might find they need one of many reflective screen e-readers devices that are easier on the eyes and use E Ink or similar technology that is now just in grayscale. Apple's iPad goes on sale in March and April, and will be available in six versions ranging from $499 to $829.