I bought this lens after reading many reviews and everyone having good things to say about this lens. After I compared it to my 24-70 f2.8L, I promptly sold my 24-70. The image quality and the IS won me over. One of the highest quality lenses that I have owned.
My only complaint with the lens as such is that at 17-20mm a little bit too much barrel distortion, shows up more on group shots, the people on the end look a tiny bit wider than they do in reality. This is easily solved by going a couple of paces back and zooming in a little more.
I have owned the 10-22 EF-s lens for some time and was unsure about the "future" of 1.6x bodies. I now know that this lens shows Canon's commitment to the EF-s range of lenses and to the X00D & X0D range of cameras, and the future looks great.