Had this to a 30D long ago. Then I was super happy.
When I bot camera so I bought the 16-35an instead.
A bit later, so I bot back into a 17-40ia, because I have not photographed as much wide angle. Then I had a 1Ds mkII, ie full sensor. Then I was a little disappointed with this loophole. Tried another similar but it was not spot on.
I would say, for crop 1.6, this is a good buy. Do you have full sensor and advice, go to 16-35an instead.