Perhaps the single most important feature on a handheld device is the display quality. If you can't read the screen easily when you are in a hurry, if the display is too dim, or if the device just doesn't fit enough data onscreen for your needs, you'll be unhappy whatever the rest of the features. Most handheld PCs have backlit screens.
Some devices have monochrome screens that display images in four shades of gray.
The 3Com Palm devices display 120x160 dpi, and Palm-size PCs run at 240x320 dpi. HPCs are available in a variety of resolutions and screen sizes. An often-overlooked factor is screen readability in varied lighting. Even more difficult, but worth considering, is the screen's readability in daylight. Although no one yet uses reflective TFT technology in HPCs, this display type is used on some Palm-size devices and improves daylight visibility while degrading the readability in artificial light only slightly.