It's not just that the screen is multitouch, it's that it's just so damn smart. I've used other touch screen devices and most of them needed a stylus because you need pinpoint accuracy, you have to be exactly inside the "button" or whatever your clicking on to work. Other hand operated touch screen devices I've used either had a wide open gui so you have large buttons to fit your fingers, or they just had smaller buttons but are a pain to use because of all the missed button presses.
The screen on the touch however knows what your clicking on, you can be in a list of small font links, and tap your finger over your selection, usually you're still making contact with the link above and the link below, but it still picks the one you're tapping on directly ignoring the ones that you are partially touching. On any other touch screen device I've used this just doesn't happen, it's just a frustration of wrong clicks. This is one of the number one factors of why this device is just so easy to use and why the interface is such a hit.
This coupled with the ease of the pinch zoom is why to me, safari on this is the best mobile browser. Sure there are other browsers with more function, but this one has way more usability.
