FACE OFF!
CONCLUSION: In the end the primary difference comes down to build quality and image stabilization, The Tamron is certainly better in both of those areas, the lenses are in fact optically similar, with maybe just maybe a slight, slight edge to the Tamron, and focus speed and accuracy are also very similar.
So if better build quality and image stabilization mean something to you than the obvious choice is the Tamron in spite of the $250 price difference, but if image quality is all you need and you can live with inferior build quality and then The Nikon is an absolutely excellent option. And a great value as well, but in terms of value if I had to choose one over the other, I would probably pick the Tamron because the build quality to me really is that much better meaning the price to build ratio is certainly justified…. Meaning overall, the Tamron is a winner but just by a nose…
GET A GREAT DEAL ON THE TAMRON 85mm f/1.8 SP FROM B&H HERE: