The zoom range came in very handy and allowed me to stay back from the crowds and reach what I wanted to. It was very sharp and the colors came through very nicely.
The Sharpness was very close to the 70-300 F4L but not quite there. That is not to say that this lens did not take great shots on my 7D.
If I had a con it would be the zoom ring. I found myself feeling and then looking for it when I was wanting to reach. The ring is pretty thin, but once I got into the habit of placing my hand on it before I brought the camera up, it was fine.
A few pros would be the lens lock, which was easy to slip on and off. I could feel for it after a short time and it switches of easily, but it was needed as the lens does creep. The sharpness is very nice and better than my 28-135 USM IS. I could tell the difference right away. Having this type of zoom range in a compact size would be very desirable for traveling.