Got the new Sigma 150-600 and took it for a quick testdrive at Castle Lichtenstein. No sharpening. Full JPG resolution. At 150, 200, 300, 400, 500 and 600mm.  Pretty impressive. I like that lens.  with F8 at 100iso. Crop from Lightroom at 100%

and sharpened

600mm orginal JPG (no compression can be found here – includes also the sharpened orignal)