Pros: Human interface, applications, capabilities, reliability
Cons: Battery life
For me, a mobile phone is my mobile access to my connected world: voice, web, email, and social networks. The iPhone is my mobile computer. With the variety of applications allowing me to connect my computers to it, my iPhone has become my primary interface to the world, with larger computers being there primarily for longer typing sessions.
This is the picture of where we're headed.
I'm aware that some people are stuck with issues around the software keyboard, and the Storm's tactile glass may be a way to address it, but from the beginning of using an iPhone, I found a willingness to adjust to the keyboard to be in my favor. Now, after a year, I type very well and quickly on it (and the auto-correct does a very good job, as well).
The app store provides a number of additional capabilities, including notes and lists that sync with my other systems, and I am quite pleased with a system that works consistently.
There are times when apps die, and other times when I decide it's time for a reboot, but I have never had a call interrupted by a system failure and I have had no lost data, both of which are extremely important to me.