I have the Canon 10-22, and really like it, use it for landscapes, street, and gigs. Think its a touch faster than the Sigma, but only half a stop or something off the top of my head. Never really had any major problems with distortion except occasionally at 10mm. A lot of people on here use the Sigma and get fantastic results from what I've seen. Also have a mate at uni who uses one on his D100 and he's never complained of any softness or distortion.