9 out of 10 points and recommendedBuild Quality is good IMO, decent macro and AF.A bit soft towards the edges wide open.
Bought the XTi body only and wanted a good standard zoom to replace the Canon 18-55mm but didn't want to spend $1000 on the Canon 17-55mm f/2.8's. Looked at the the Sigma, Tamron, and Tokina f/2.8's and decided on the Sigma. Haven't regretted it to date. Takes excellent pictures even at f/2.8, even though they are a bit soft....not a problem with the portraits I take.reviewed April 21st, 2008 (purchased for $419)
For anyone that wants a good constant lens at half the price of the Canon, this is the one.