I have waited for this lens for quite sometime and have not been disappointed at the IQ. I tried using the Tamron 18-300, but the IQ for me was sometimes lacking in sharpness. Others may be satisfied ... I believe it is subjective. I also like having the aperture ring vs using the back command dial to set the aperture. It's all about what placement of that control YOU want. This goes perfectly with my XF 16-80 as a travel pair and I also have the option of purchasing the 1.4 teleconverter LATER after I perfect my technique above 100 mm focal length. The right lens for me, but do not let my review bias you against the Tamron. To each their own ....
I am so impressed with this lens. It was an upgrade from a Tamron lens and it exceeds my expectations. I would highly recommend this telephone lens because of it quick focus and sharp photos.