I've heard touchscreens aren't all that they are cracked up to be and that something that gives more tactile feedback such as a keypad would be better for input into a carputer. The reason being so you can operate it more easily by touch and don't have to take your eyes off the road. With a touchscreen, you have to momentarily take your eyes off the road to make sure you are about to press the right thing on the screen.
The reasoning at least does seem sound. Anybody here tried both approaches and can confirm or rebute this?