Excerpt: Overall, better than two kit lenses put together. On my D7000, it is bright enough. Surprisingly sharp throughout focal length. Auto-focus is fast, quiet, and accurate. It searches a little in low-light, but not too bad. Lens creep is a small issue, but the lens lock works well enough for me. Feels sturdy and tight (maybe a little too tight). The hood is nice, but it took me while to figure out that it won't lock in place unless the Sigma logo is on the bottom.
Pros: Consistent Output, Durable, Fast / accurate auto-focus, Nice Bokeh, Rugged, Strong Construction