This lens is one of the real sleepers in the Canon L range. I sold mine when I got my 300 f/2.8 but I'm seriously tempted to get another one primarily for it's incredible light weight, sharpness wide open, surprisingly close minimum focus distance, 77mm filters and the small space it takes up in the bag.
I'm sure it's rather small and lightweight - no problems with handhold shooting for 3 hours or walking with it in a park. IS could be better and contrast - then it would be just perfect. Shooting against light makes some problems but in overall - the IQ/price factor is really good.Legia - Jagiellonia. 1:2
, on Flickr