http://www.photozone.de/Reviews/176-canon-ef-17-35mm-f28-usm-l-lab-test-report--review
Where are you buying it from?
Isn't that 17-55 almost 3 x the price ?
Save up and buy a second-hand 17-55mm f/2.8 rather. Or the Tamron/Sigma options if the Canon is too expensive.
Save up and buy a second-hand 17-55mm f/2.8 rather.