Ill be honest with you, I was very close to sending my 12.9 back and holding onto the Air 2 instead, took me a good 3 or 4 days to love the 12.9(the waste of screen space with the blown up apps was actually incredibly irritating at first)
Thats actually mainly what I want the Mini 4 for, books and portability, Ill be using the 12.9 most of the time though, once you get used to watching movies on that screen you won't want to go any smaller, one bit of advice id give anyone getting the 12.9 is get a good case for it thats gonna make it comfortable to use, it can become quite awkward and unwieldy I find when its naked
[doublepost=1491563157][/doublepost]This is case I got
https://www.amazon.co.uk/gp/product/B014ZZIKOI/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Its not as fancy as the Apple one but its very versatile and makes the iPad so much easier to use imo, can't recommend it enough