I've used it and am happy with the results *mostly.* However, I never get the kind of tack-sharp photos I see elsewhere, even under what seem like perfect conditions. I'm using it on a Canon 60D body. I did a focus test and found that it consistently seemed to be focussing just a little closer than where it thought it was focussing. I have not yet taken this issue up with either Sigma or with Canon...but that might be why my images aren't as sharp as I think they should be.