I wanted a 32gb...after listening to comments here and at T-Mobile, I wasn't sure there would ever be one, let alone soon. So I bit on the 16gb.
As I've said elsewhere, I think it's ok. I'm an experienced user with lots of apps. I reinstalled 2 years worth of stuff, plus things I hadn't had room for before. And I still have about 7 gigs free internally.
Now, to be sure, the T-Mobile response of "use the card," isn't very satisfying. The card is not as big a solution as one might think, because the new version of Android doesn't allow you to move apps to the card. Some apps may automatically install there if large, but most apps go right to main memory on the device. Most of my card is media storage--ebooks and MP3s as a result. Another problem that still would have made me buy a 32gb if there was one---there is no universal "clear cache" command that I see any more either. I downloaded an app called History Eraser Pro simply because it contains that feature. I don't really much need it at the moment, but if it ever were to get tight for space, that would be very convenient.
On the space saving side of the ledger, while you can't uninstall Samsung's native apps or included apps that I don't use like ChatOn completely, you can still reduce them to factory state rather than letting them update. The update versions always seem much larger. So I "uninstalled" ChatOn and Chrome, for instance.
Still, the end of the story is this: I have a mature setup. It has everything I've thought of for over 2 years. I won't be needing a lot more, I presume. And I still have about 7 gigs free. That seems reasonably safe for the practical life of the phone as long as I use the card for things like MP3s, videos and the like....and needless to say, with so much headroom, I've been rather extravagant. If I had to, I could certainly live without some stuff I am carrying at the moment. But 2 years of computing has gotten me to a point where I'm using less than 2.5 gigs of space for apps and their content, including some very large ebooks that Kindle seems to like on the main device rather than the card. Nearly seven more gigs still free seems like reasonable headroom for the foreseeable future as long as you put that media content like MP3s on the card.
I just made another call to T Mobile. I see that have start showing the black mist on their website. For a while it was only the white. Anyway, I asked them about the 32gb release date again, and again, the rep wanted to tell me to just add an SD card. I hate that, I am a 2 or 3 month old newbie, what I know about these phones I have learned reading this forum. Even I know, you can't install apps on the sd card, how come the reps don't know that? ...
Well, in fairness, this is a relatively recent change. They should know, even if the phone and JB 4.1.2 is fairly recent. But it used to be standard practice. I can understand why they're confused. I certainly was after using another device with a different system for a couple of years.
My wife has the 16gb, and I got her a class 10 sd card 16gb,and she is tickled pink. Even let me use the S4 while I sat in the car waiting for her to finish shopping.. 
Facebook
Twitter
Instagram