"This has become a lens I must have with me. Use it appropriately and it is sharp with minimal to no vignetting." bhphotovideo.com
"In my use of the lens with a Sigma mount, I have found it to be very good. The build quality is very good." bhphotovideo.com
"Even though the info says it's only for Sigma camera's, it works very well on my Nikon D90." bhphotovideo.com