Upload & Sell: Off
Can't help with a comparison with the Tokina 12-24, but I own both the 10-24 and 12-24 Nikon lenses. To me, having 24mm at the long end is useful enough I've not been interested in the 11-16. The only "disadvantage" to the 10-24 Nikon vs the 12-24 NIkon is f/4.5 vs f/4 at the long end, and that hasn't mattered to me one bit. It's only 1/3 stop exposure difference. OTOH, on the short end, it's a bit faster than f/4...by 1/3 stop.
The sharpness seems to be the same to me, but I'm not really a pixel-peeper. I do notice things like that in prints, though. I think the 10-24 sharpness is about as good as it gets with DX in that zoom range. While important to me, it wasn't the deciding factor between the lenses, and neither was the build quality or the end of the lens moving in and out when zooming (the 10-24 is sturdy enough). What mattered to me was 10mm. It's a big difference vs 12mm on DX. Now, I don't shoot that much at 10mm, but it's nice that it's there when I want it. I really like my 12-24...it's an old friend that delivered a lot of good shots. It was on my D70s in late '05 through a D200 and onto the D7k, but I've had a few shots ruined by the IR hot spot. On my non-IR D200, it occasionally gave a purplish/violet cast in the lower center of images shot in harsh light, including a set shot with hard window light in Lincoln's mother's log cabin that put the purple all over the foot of the bed and the wood plank floor. No such problems with the 10-24. I can also use it on my IR converted D5100, no problem. All on it's own merits, I'd get the 10-24 Nikon.
My last comment is this: I work in New Guinea, and I brought along a D7k, 17-55/2.8, 10.5mm fish, and a 10-24. Right now, my 12-24 is sitting in a closet in the USA. I'll probably sell it on my next home visit.