While earlier dalliances with the Wii U's "WiiPad" controller didn't include touchscreen interaction, a hands-on session with the "Measure Up" tech demo told me all I needed to know about the touchscreen technology behind the device.

It has a stylus. A recess in the upper left of the unit hides a small, white, roughly DS Lite-size stylus. Interacting with it brings up the familiar feeling of poking at a DS screen. Much like the handheld's bottom screen, the Wii U touchscreen doesn't respond perfectly to tracing with a finger. And multitouch is right out. Touching two spots caused the line I was drawing to jump to a point between them, much like the DS.

That suggests that Nintendo opted for a cheaper resistive touchscreen, instead of a capacitive touchscreen like the iPhone uses.

http://www.joystiq.com/2011/06/07/wii-u-controller-has-a-ds-style-touch-screen/#comments

no expert but guess it might be good on the price front?

I don't know what to say still, Nintendo has confused me greatly with this and until I see some first party games and how it uses it I'll still be confused unsure if I like it or not..

Resistive is also more precise than capacitive, as well as cheaper, so there are benefits there