In two key respects, using the iPhone app seems superior to using a Kindle. First, the iPhone’s screen is brighter, and supports color, so book covers and illustrations in my test books looked much better on the iPhone than they did on the Kindle. Second, the iPhone is smaller and thus much more portable.
Exactly. And if someone delivers that with openness, Kindle will have a lot less success.
Walter Mossberg's Mossblog: First impressions of Kindle on iPhone
Check the "Kindle" tag below for more.