That uniqueness may be just in the fact that our brains were "trained" during the billions of years of life on Earth, with all the quirks of that particular environment. That may indeed be hard to replicate exactly, so it can be imagined that AI will not match us in some particular tasks, just as it is hard for the aviation industry to match the characteristics of bird-wings. (which they can of course outperform along some, but not all parameters)