Decided to take advantage of the Canon rebate and picked up a new 24-70. I was a bit hesitant after reading so many user reviews of focusing problems and other issues. I took a bunch of shots of my one year old son and eagerly waited for the pictures to transfer to my computer. I am happy to say that there are no focusing problems whatsoever with mine. The one area that people don't seem to emphasize enough is how quickly and accurately it tracks moving objects. The focusing on my 5dii just improved significantly. I'm now able to get sharp photos of my son as he moves about.