I had the same decision to make. A local pro advised me to get the 24-70. Then again I already have a 17-40 f/4L to get down to 17mm. I ended up with the 24-70 2.8L and I'm not sorry. Its heavy but comes with L series pedigree and drips quality. On the downside its not IS so you are back to 1/focal length shutter speeds unless you are on a *pod. Dont use it outside without the hood.