Have shot with this lens 2 days now.
Sharp allready from f. 2.8.
Sharper than Nikon 12-24 (from f.4 and down in the area 12-16), but Nikon 12-24 is more versatile - goes to 24mm and here - at 24 mm - the Nikon 12-24 shines.
As sharp in the center as the new Nikon 14-24 allready from f. 2.8, but not in the corners - the Nikon14-24 is a clear winner here.
Flare/ghosting: Worse than Nikon 12-24, but better than Nikon 14-24.
About the same, maybe less CA, than Nikon 12-24.
Today I suddenly could not get AF, whatever - turning of and on, but then took the lens off and mounted it again, and then the AF was OK again.
I have experienced that with one or two Nikon lenses, too, when the lenses was new, and I hope it is the same:
Some tiny metal in the new lens has to worn off.