Not having to constantly change the aspect ratio of pages. With my touch, I was always pinching & pulling & reading partial pages. With the pad, it's the perfect sized of web pages so I can read without all the scanning.
The mobility of these devices is my overall favorite thing though. It's a book. It's a gaming system. It's a net browser. It's a note taker. A GPS. A cookbook.
It goes everywhere & does everything.