I don't have personal experience with the suggested lens, but I did a quick check on a lens review site I use:
http://www.photozone.de/bindex2.html
They suggest this lens has vignetting at its wide end. If you're not using a full frame sensor, though, this might not matter. They also don't like it optically very much. Of course, they don't rate the Canon EF 28-135mm f/3.5-5.6 USM IS much higher.
I read the forums as dpreview.com, and at least the Nikon SLR forum is filled with people who are very critical of their lenses. If it is the same in the Canon SLR forum, then you'll find a wealth of info about lenses there.