Here are some test photos from my new Sigma 150-600 Sports.
Remarkably little CA @600 mm f/6.3
I suspect my next new toy will be a D500...
Noise levels @ISO 3200 aren't low with the D300, but the photo is quite nice for a cropped capture @14 m. I'll have to play around with it much more before I can draw any conclusions on focus accuracy.