According to trusted sources in communication with Ryan at Engadget the touchscreen keyboard on the iPhone leaves something to be desired.
As noted, the iPhone does not have a device mounted keyboard, but a virtual, touchscreen keyboard.
Ryan reports that it’s too easy to hit more than one key. Users are recommended to use one finger rather than thumbs, the kys are so close together.
Also, the touchscreen reportedly requires some heavy handed pressing in order to register the keys being selected.
What do you think about iPhone having to physical keyboard?