My biggest concern was the keyboard. Having used the Prada phone, I expected the worst. Surprisingly, the iPhone keyboard starts to feel comfortable fairly quickly. Within a few days, I went from typing two out of every three letters incorrectly down to just one in five wrong. That gives hope.
E-mail, though, is another story, making me long for my BlackBerry. Sure, Yahoo allegedly provides the same RIM-type push mail. But it's simply not as quick or easy to knock out a sentence or two on the iPhone.
More annoyingly, it appears there is no way to delete all your mail at once. You have to erase each individually. Even worse, it seems many of us find 50 or so older messages transferred over. Delete them one by one? Sure. But then another 50 old ones pop up. Mail needs work!