Apples latest videos showcasing iPad as a serious work tool for different kinds of tasks were produced using iPads. In this video they show how they did it.
Yes, Apple has almost unlimited resources to make that work, but iPad really is a powerful tool, which has been proven again and again.
This spring it is six years since I switched from Mac to iPad fulltime for all my work (and entertainment). Lots has happened since then. Everything is easier now. Every update of iOS improves my workflows and every new iPad release has made my work faster. It has come to the point where I no longer have to update the iPad every year. It is as fast as I need it to be.
I have worked on all sizes of iPads, except the newest 11 inch iPad Pro. 7.9 inch iPad mini, 9.7 inch, 10.5 inch Pro and 12.9 inch Pro. Currently, the iPad Pro 10.5 is my favorite size. Sure, the 12.9 inch screen is better to work on in many situations, but it is also much heavier to carry around and impossible to work on lying in the sofa or bed. The 10.5 Pro iste best compromise for me.