I got this instead of the Nikon I mentioned before mostly due to time constraints. I wanted to use the lens while I was visiting Boston over the holiday, and the Nikon wasn't yet available. I'm not sure when it will be available, actually. But, never mind: I'm very happy with the Sigma, though it's a bit of a bear to lug around. I'm glad my D40 body is tiny and light.
I used it on this set:
And here's an exploitation of bokeh: