If you need superwide on a 1.6x crop body, this is about your only choice. For $690, it's priced fairly.

However, it was too wide for me. I didn't like the perspective distoration at 10mm. See the 1st Epcot picture below where my nephew's feet are larger than the Epcot ball. :-)

The sharpness and colors are also a little weak.

In all fairness, I never tried the 10-22mm for landscapes where it supposedly does pretty well.

I returned the lens and ultimately ended up going with a 5D and the excellent 35mm f/1.4L (35mm is like 22mm on a 20D).

I recommend the The-Digital-Picture.com for comprehensive reviews.