the common factor here is...
... that people who have a large smartphone are going to use it as a small tablet with telephony?
I use my Xperia Z2 (tethered) with my Z1 Compact - the Tablet is more for pdf's, Zinio, browsing and the compact is for txt/hangouts/facebook/twitter/Good.
At meetings, it's the Tablet as you have to read minutes and take notes, so that's easy with the Swype (etc ) keyboard.
cursus equorum
I agree about having a decent data tariff!
Biting the hand that feeds IT
