Dropbox is of course a functional equivalent to external storage and not app space. If you buy the 16GB S4, do not expect to do much gaming as far as the newer 3D games. I fill that up with just six games, considering other apps and the OS needs some of that 9gb of space too. Considering how much of the "16gb" is free, seems obvious a 32gb version should be offered.
On a positive note, better to be "stuck" with my 32gb S3 than my G1
I kept that for the two years and then bailed to VZW for the Incredible. I cried back then about no 3.5mm audio jack and low storage too
Odd the carriers appear to be going full circle on app storage while misleading consumers they can put apps in the sd cards and use the cloud. This in spite of Samsung offering 16, 32 and 64GB versions.