Storyboards have a number of advantages over regular nibs:
With a storyboard you have a better conceptual overview of all the screens in your app and the connections between them. It’s easier to keep track of everything because the entire design is in a single file, rather than spread out over many separate nibs.
The storyboard describes the transitions between the various screens. These transitions are called “segues” and you create them by simply ctrl-dragging from one view controller to the next. Thanks to segues you need less code to take care of your UI.
Storyboards make working with table views a lot easier with the new prototype cells and static cells features. You can design your table views almost completely in the storyboard editor, something else that cuts down on the amount of code you have to write.