The superb distortion control means this can be a rewarding lens to use. However the sharpness has been a major disappointment for me. UWA lenses often have the foreground to the edge of the image where the lens is weakest, but even centre resolution isn't on a par with the price bracket.
Rectilinear with excellent distortion control, even at 10mm; Light and compact; Decent but not exceptional build quality; DPP lens profile completely eliminates
Price (though it has dropped below £500 recently so its less of an issue now); Not particularly sharp, even in the centre; More chromatic abberation than I expected at the price