GPS Phil wrote:
While I don't have that particular lens, I do have two of the Art Series lenses, 18-35 1.8 DX, and the 24-105 f4 FX. They are both built like tanks and will stand toe to toe with almost anything. And that is just my opinion, based on user experience. I have heard nothing but good things about that lens.
Phil
I bought the 24-105 last year and tested it extensively. I even posted test shots between the Sigma and my Canon 18-200 kit lens here. About half the viewers could see no difference and the other half thought the Sigma was only slightly sharper. Prints from the two lenses showed no differences. The Sigma was only better in the corners under high magnification. I returned the lens and have new-found respect for that cheap Canon kit lens.
Lesson learned: compare the new lens very carefully to your old one and be very critical of what you see, not what you imagine.