What happens when a phone runs out of storage and pictures are taken?
iCloud storage price : http://support.apple.com/kb/HT5879?viewlocale=en_US&amp;locale=en_US

So it depends if you have a good network connection for download what you need when you want (photos with iCloud, musics with spotify...) or if you want all your photos, all your iWork documents and all your stuff on your iPhone all the time. 

It depends if you take a lot of videos, if you download a lot of big games from the App Store... 

In fact, it depends of your money ^^