Its big, it's heavy, but it takes amamzing pixs. I use it on mu 30D and have been blown amay by the sharpness, contrast, and colors. I got fed up with 3rd party lenses that produced soft images. Not so with this big boy. Just got back fromn a 2 week trip to Spain and the images are incredible.
I bought this lens to have a lens that covered an all around focal length. This is it. You feel like a real pro using this lens because of the smooth focus and handling. Also because of the images you get. Sharp, crisp and satuarated. They use diferent glass in the L series lenses and it shows. I'm saving my pennies for another Canon L.