In the June 2011's Popular Photography magazine (Canada, hard copy, pg. 90) in an article titled "Star Power", on a one page overview of the Canon 70-200mm f2.8L IS II USM, the author (Julia Silber) claims (when talking about optical sharpness at 70, 135 and 200mm) that "While a significant improvement over its predecessor, which never rose above Very Good, its numbers were slightly below the comparable Nikon and Tamron glass, which scored excellent at all focal lengths."
I am assuming the predecessor could be any one of the Canon L 70-200mm, likely the f2.8 IS version. I don't own this lens and am still in the process of gathering information on the f4 (no IS) version which is the only one I will be able to afford but... So far all I have read was excellent when it came to the optics of these Canon lenses.
The question is: Which Tamron lens that is "excellent at all focal lengths" is the author talking about? Can someone point me to a good review or share their thoughts? (Purely optical quality preferably)