Pros and Cons of Touchscreens

The following overview lists advantages and disadvantages of touchscreens and summarizes their characteristics.

Touchscreen Pros

Direct: Direct pointing to objects, direct relationship between hand and cursor movement (distance, speed and direction), because the hand is moving on the same surface that the cursor is moving, manipulating objects on the screen is similar to manipulating them in the manual world
Fast (but less precise without pen)
Finger is usable, any pen is usable (usually no cable needed).
No keyboard necessary for applications that need menu selections only -> saves desk space
Suited to: novices, applications for information retrieval, high-use environments.

Low precision (finger): Imprecise positioning, possible problems with eye parallaxis (with pen, too), the finger may be too large for accurate pointing with small objects -> a pen is more accurate.
Hand movements (if used with keyboard): Requires that users move the hand away from the keyboard; a stylus requires also hand movements to take up the pen.
Fatigue: Straining the arm muscles under heavy use (especially if the screen is placed vertically).
Sitting/Standing position: The user has to sit/stand close to the screen.
Dirt: The screen gets dirty from finger prints.
Screen coverage: The user's hand, the finger or the pen may obscure parts of the screen.
Activation: Usually direct activation of the selected function, when the screen is touched; there is no special "activation" button as with a light pen or a mouse.