[mmariani]

Another reason to seriously consider using nibs instead of hand coding UIs is Auto Layout. It is way easier to deal with that API in IB. Of course you can in code too. But every new API has its problems. Most commonly, they're a pain to deal with due to unexpected behaviors and incomplete documentation.

You all have been warned! ;)

[fphilipe]

Auto Layout is pretty much the only reason nowadays I'd use nibs at all. Unfortunately, they are iOS6 only. If you want to support the previous major version you'll have to wait until iOS7 before you can really use that.