For the first time ever, I didn't get through a month with my normal data plan and upgraded.
I figured this was because with all the "setup the new phone stuff" I wound up experimenting more and downloading more frequently when off wi-fi. I have also been considering whether I am just plain using more with the Note 4, but the next month will give me a better picture of that. I'm using the same apps. I can't see why offhand it would automatically be more of a data hog. If some default has been restored that I'd turned off before, the simple answer is to find out what and turn it off again.
But in terms of "new setup," the second highest usage was Google Play store--45 megs. That would seem logical. The highest was "Android Core Apps" at 112 megs.
Note: Flipboard used a mere 17 megs of data. It is not the main or sole reason I went from a typical 700-800 megs in a month to what would've been about 1.3gb (had I let it complete the cycle, which still has a week or so left). Facebook was next at 16 megs. Nothing else was over 10.
At the moment, not convinced it is anything but a 1st month aberration, but we'll see how the next month goes. Although next month has some travel planned, and that always uses more data.