For years I have used the Tokina 12-24/4 DX which is an excellent lens with an affordable price tag. Now I use the Nikon 14-24/2.8 FX which is absolutely outstanding - easily one of the best lenses ever made by Nikon. The lens is expensive, kind of heavy and has no filter threads.
I have the sigma 10-20mm (cheapest version) and I really love it, I think the bottom line is that there is not really a dud in the line up of options for you, Tokina, Sigma and Nikon (of course) all produce good w/a lenses, do you intend to shoot low light?
If not then maybe save some money and not chose the Nikon in this instance…?