I own (2) Nikon D700 bodies and Nikon 17-35 f/2.8, 16-35 f/4, 24-70 f/2.8, 105 f/2.8 VR macro, 70-200 f/2.8 VRII lenses.
I also own the Sigma 85 f/1.4 and the new Sigma 35 f/1.4. Both of these Sigma lenses are as good, if not better, than the Nikon versions. Same with the Sigma 50 f/1.4, which I do not have.
The Sigma 70-200 is a decent lens at a significant discount to the Nikon version.
3rd party manufacturers are giving Canon and Nikon a run for their money.
You really should look at alternatives before spewing your BS.
Prove you own it or its false, "Troll".