The lens was tested on Nikon D5300 model by DXO MARK Lab team and hasn’t been tested yet at semi-pro or professional models, but if you look at the test-score of the lens then you will be amazed. The Tokina AT-X 14-20mm F2 PRO DX lens showing overall score of 25 whereas the Nikon AF-S DX NIKKOR 10-24mm f/3.5-4.5G ED Lens scored only 16 Marks.
The most important part of a Lens is apertures, the Tokina 14-20mm features fixed F2 aperture whereas the Nikon 10-24mm lens features variable aperture range of 3.5-4.5. Despite of having constant F2 aperture range the price of Tokina lens is bit less and Tokina is also more sharp compared to the Nikon.
Get the Tokina 14-20mm lens from B&H
source- DXOMark Lab