Nikon 70-200 f/4G ED VR AF-S or Sigma 70-200mm f/2.8 APO EX DG HSM OS FLD

Assuming you can fetch a similar price for both, my vote for the Nikon as well. Don't just be lured by the extra stop between f/4 and f/2.8, the Sigma was quite weak corners at 200mm and f/2.8. The Nikon is much sharper across the frame, and probably more resistant to flare and ghosting. I would go with the Sigma if I new for sure that I was always going to prioritize foreground/background isolation over sharper across the frame results. It really depends on what your shooting priorities are.

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