I have three: iPad mini3, iPad Pro 9.7, and iPad Pro 12.3. (I have had the mini3 for a while. The big Pro was given to me as an office perk a year ago. I like it a lot but find its size a bit daunting for a carry-around machine, so I bought myself the Pro 9.7 ... that's why I have all three. ;-)
The iPad Pro 9.7 with its case and Keyboard Cover is my standard carry-around portable machine nowadays. It has the best screen of the three and the performance between it and the bigger Pro is so close as to be almost indistinguishable. I do most everything with it that I would do with a laptop.
For photography, I have the Leica SL App installed and can use it as remote and controller for my Leica SL, and with the Lightning SD Card Adapter I can bring over images from either the SL or M-D for processing. I have PhotoRAW, SnapSeed, and Photogene 4 installed for image processing. With Keynote, iMovie, and Pages I assemble presentations of photo work. I also write with it, and illustrate my writing with photos and with drawings made with Paper by 53.
It's quite a versatile machine, and fits in most of my camera bags easily should I want to carry it that way. I generally can get about two days of fairly heavy use on a charge with it.
G