But it is not 16gb, it is 9.7gb and about 500mb needs to be left alone so some apps work correctly and you can update apps in the market.
Effectively, the 16gb S4 is 9gb. The S4 for storage is similar to the G1, when correlating size of storage to apps size when the G1 launched. Catch is at least with the G1 you could do apps2sd. Not happening for most with the S4. Back then the G1 storage was fine for most, until a few months later.
Let's hope for 32gb models