I went through that same back and forth for a couple of years. I loved the iPad 2 and iPad 3, but to me the original iPad Air was the ultimate iPad design. I had to have one, so I upgraded that year. It felt so well designed and so streamlined, and I always had it with me almost everywhere I went.
But I started expecting more out of it. I used it so much that I wanted it to be my computer. I tried a zillion different keyboard cases and hated them all, and iOS just couldn’t do enough at the time to morph into my every day OS. I decided that what I really needed was a new MacBook Pro, so I sold the iPad Air to help pay for it and went about a year without having an iPad at all.
Worst mistake I ever made—I SORELY missed my iPad. I tried to fill the void with an iPad mini 3, and I really like the minis in general, but it was not doing it for me in the screen size and productivity department. I gave the mini 3 to my wife to replace her aging mini 2, I sold my MacBook Pro, and I bought the iPad Pro 9.7” as soon as they came out. By that time, iOS had definitely caught up with my workflows, and I was doing all of my personal computing on the iPad. (I still had my work MacBook Air to fall back on if needed, and I did need it sometimes.)
Now I’m on the 10.5” Pro, and it is the only computer I need. I love this thing to death. I don’t have it in my budget this year to upgrade to whatever the new Pros are, so I’m going to stick with my 10.5” until next year. It feels good to be using an iPad daily again. I know not everyone feels like they can replace their computers with iOS 11 and an iPad—I definitely didn’t feel that way a few years ago. But I’m a much happier camper now.