I have the older version of the 11-16mm Tokina, and have found it to be excellent, not only in it's sharpness etc., but even more importantly, in it's great colour and contrast.
I bought it for my Canon 60D, but it also works very nicely on my 5D3 at 15 and 16mm (any shorter and it vignettes pretty seriously), but 15mm on a FF camera is very wide and wide enough for interiors etc.