Just got a new 24-70 II and I must say that my initial images are, well, disappointing. I was hoping for something along the lines of the ridiculous sharpness of the 70-200 II. Sadly, what I'm seeing is much closer to my 28-135.
If you look at this .cr2 file in DPP (http://home.comcast.net/~sal6/BY5R6357.CR2
), you'll see the focus point is the white and purple cluster of flowers. However none of the flowers in that cluster are what I would consider remotely sharp -- this was taken at 70 mm, 1/320 sec, with f/2.8, ISO 100. With those, I don't think it's the lack of IS.
All of the photos I've taken are like this, without regard to shutter speed (even up through 1/2000 @ f/2.8 (ISO 150)) -- also, this is actually one of the sharper ones.
Maybe AFMA will help. But I'd (naively?) expect an AFMA problem would mean that something, somewhere in the image would be sharper. I suppose it's possible that there's nothing at the right depth...