My 2¢


I wouldn't buy a lens at this focal length with out IS. So I would definitely take the 4.0 IS over the 2.8.


I had the 4.0 non-IS and had a tough time finding uses for it. I have the IS 2.8 now and couldn't be happier. It is a beast though.


If I were a wealthy man, I'd own both the IS versions.