When creating a UIBarButtonItem using the standard UIBarButtonSystemItem values of UIBarButtonSystemItemSave or UIBarButtonSystemEdit you end up with text-only buttons.
The text-only buttons are an issue with the iPhone Duo since such buttons do not get put in the vertical sidebar.
This is a problem with a view controller with scrollable content. The text-only Save or Edit buttons can scroll out of view leaving the user confused about how to complete their work on the screen.
Related is the UIViewController editButtonItem which gives the standard Edit/Done toggle button. Since the button shows the text "Edit" the button doesn't get put in the vertical sidebar. This is despite the Done display being shown as a checkmark icon.