After taking well over 700 images the past few days at this confernece with the new Canon EF 24-105mm f/4L IS USM, I can report that it is an excellent and versatile tool. I like its weight, it was easy to get sharp images, and it worked quite well in a large, dark ballroom. The orange-colored walls in the meeting rooms drove me crazy re color balance, but that was not a lens problem.
I used to have Canon’s Canon EF 28-135mm f/3.5-5.6 IS USM. This new lens is fine replacement and upgrade. It will be my major “walk around” lens