My Short Review
The title says it all! Despite its autofocus inaccuracy on my Canon EOS 350D/XT, it is well worth keeping. My first copy of this lens had to be sent back to Sigma for repair even though it has produced sharp images (1st lens copy samples: London Street, Borough Market, Food). Instead of repairing it, Sigma gave me a new lens. Not sure if this was because my original copy was not worth repairing or was it Sigma’s tactic to keep customers happy (read my dpreview thread here) Either way, I am happy with this lens (2nd copy) although autofocus remains inaccurate randomly without specific reasons. My conclusion, after reading many comments from others in dpreview (eg. here), is that the problem lies within Canon 350D/XT itself. I have developed a method to minimize the number of out of focus shots - half-press (to AF) several times before full-press to release the shutter. This method seems to work well 90% of the time! Below are some samples taken today (19th May 2007) in London. It was a sunny day but part cloudy. Samples were converted from RAW using Capture One Pro (V3.7) with my usual exposure/saturation, white balance, sharpness and cropping adjustments. No other post-processing was done after conversion from RAW to JPEG. | 
