Thanks for the compliment, Allegretto! Of the two lenses, I'd personally stick with the 24-70, especially if it's the 2.8 Mark II. Even the f4 would be my preference. I'm a CPS member (and have been since 1982) and try a lot of different equipment from Canon. I never really cared for the 24-105, but that's my personal experience. Other's may argue otherwise. I actually have a good copy of the 24-70 Mark I. For my work I use that lens, also the 50/1.2, 85/1.2, the 135/2 and the 70-200/f2.8 II. Of those, I use the 85/1.2 and the 70-20 0by far the most. Many years ago, when long lenses were the rage in fashion, you couldn't pry my 300/2.8 from my hands. I still love that lens, as old and but sharp as it is, but styles change...