first, there are some examples on pbase of images taken with at least one variant of this lens athttp://www.pbase.com/cameras/sigma/28mm28 (be aware that several are with the sigma sd9/10 dslr's).

however, as with any lens maker, you can't judge the entire company's quality by a single lens. all makers have dog lenses along with great ones. similarly, I can't show you shots from my sigma 105 macro and give you any real evidence as to the quality of the sigma you have.

anyway.
allan