Check out Howard Forums, it's discussed quit a bit.
General consensus is the iphone is not a pda/work phone, the Blackberry and other devices similar to it are and can't be compared. Trying to remember off of my memory, the Blackberry allows for a lot more email options than the iphone.
I've played with the iphone, and it looks cool and is nice, but it's still not worth it. I'm just one of those people who can't buy into the hype of apple products outside of their ibooks. I've wanted one of them for a long time.