Clearly we are spoiled for choice, as modern cameras and lenses are universally excellent. You could start a thread for just about any mirrorless lens, even a cheap third party, and post amazing photos that would convince everyone they need it. Of course the lens discussed here truly is outstanding, as the $4800 price tag would suggest. I started with the also excellent (and more affordable) 180-600 which has the same aperture, is almost the same size (slightly longer), and has the added convenience of a zoom. I sold it and got a used 600PF on this site, so the obvious question is why choose this over the zoom.
For me the only reason is weight. The 180-600 is still handholdable and is a bit lighter than the Sony equivalent 200-600. However, I found it got a bit heavy after walking around for an hour or so. Some people will not mind, but for me it was just a litte too heavy. The 600 is the ideal weight, being the same as the 70-200 f2.8 (which I also own). The fixed lens also presumably takes teleconverters better. People say it is sharper as well, but the zoom was plenty sharp to me so I don't think this is a major factor.
Post processing can do wonders for photos, but in reviewing a lens (as we are in this thread) I think it is helpful to post images straight out of camera. So here are a few recent shots I grabbed, downsized for internet (and watermark added), but otherwise uncropped out of camera JPEG files.
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