I used phone for SMS, wechat, viber, messaging, email, calendar schedule, facebook, little bit of picture taking (food, for fun), cloud services.
I used tablet for Skype, email, reading online articles (currents, flipboard,), YouTube, play little games, calendar schedule, Facebook maps, some ftp , cloud services, read PDF, ebooks , edit documents.
As you noticed , I email on both my phone and tablet, as I add same email account on both devices and so with other accounts like Google plus and Facebook.
I don't really watch full movies on tablet or play super intensive games. So I was thinking if xperia z ultra is worth the change for both my n4 and n7. I want to do all things on 1 device so it won't be redundant and most of the time I at my office so i have a 15" laptop to do other stuffs.
Also would like to know if xperia z ultra camera is good even without flash. How it compares to the camera on Nexus 4? Which one is better ?