A combination of fast operation and AF and very good quality results has resulted in a beautiful lens. It is heavy, but manageable, is very easy to use and it locks on to the subject virtually every time.
Very good sharpness levels, Vey well-controlled central CA, Modest vignetting, Modest distortion levels, Fast, quiet and accurate AF, Options of zoom operation, Beautiful bokeh, Virtually no flare, Effective 4 stop OS, Moisture and dust resistance, Reasonable price