It appears that the iPhone might indeed be taking a large bite out of RIM's Blackberry-flavored apple. See this story.
Many of my Bridge students valued RIM last summer as part of the Business Bridge curriculum. I wonder if you want to go back and change some assumptions?
I use my iPhone more than any other device I have owned. Why? Easy to use, it works, zero marginal cost, and it is cool. Not a bad mix of qualities.