I have the 70-200 f4 L IS and I love it. It is light and pretty fast. Extremely Sharp and the IS is AMAZING. I do dream of upgrading to the 2.8 IS II but that will be awhile. I have shot 2.8 NON-IS and wont look at that lens (I shoot weddings and Concerts Mainly). I prefer the extra stops from IS rather than the extra stop of f/2.8. Some day Ill get the 2.8 IS II.