I've put this filter on many Canon lenses and it's worked just fine with no perceivable loss in image quality EXCEPT on one lens.
For about a week, I used this off and on a 24-105/4L IS. Near the end of the week I noticed a faint scratch/abrasion in the dead center of the filter as well as on the front element of the lens. Thus, I stopped using it (on the trip). When I returned to civilization and the land of the internet, I did some searching and found quite a few other folks (on dpreviewDOTcom) complaining about the same issue with the Tiffen filter and their 24-105/4L lens.
All in all, I'd recommend this filter, but try it on all the lenses you intend to use to make sure there's some clearance between the filter and the front element.