I ditched my iPad Air a few months ago, missed it after about a month, and bought a mini. I have tried the iPad Pro too, and of the three sizes, I think the mini is my favorite so far. I love taking it with me if I'm going to an appointment or something and know I'll have time to read a book or do some browsing. For me, it's also the perfect sized gadget for those nights where I just want to go to bed and watch a TV show or get some reading done. The size and weight are ideal for that.
One of the main reasons I initially ditched my iPad Air was that as thin and light as it was, I was not doing much with it. It sat in my backpack most of the time unused, and I figured out that I was often choosing my iPhone instead due to portability. When my wife got her mini, I immediately thought, "THAT is the iPad I need!!!"
So I do love iPads, but I'm finding that owning a larger one is a bit of a waste of money in my case. For the things I do with an iPad (and yes, I even do some "work" on it), the mini is the perfect size.