I have been contemplating buying the Z 100-400mm but in the meantime I've kept my 70-200mm w/Z TC 2x glued to the Z9 and I am convinced it's good enough. It is incredibly flexible, without the TC it's capable of close-in shooting of birds/wildlife or landscape, or portraits; with the TC it provides a 140-400mm f/5.6 Z lens that is incredibly sharp, focuses fast and tracks birds-in-flight even at a great distance. I just wonder how much better can it get and is it worth spending another $2600?