I'm very jeleous. I've heard that lens is one of the sharpest around for a zoom. I guess it's sharper than the f2.8 version. The common decision people have a tough time with is to buy the f4 IS version or the f2.8 non-IS version. They are about the same price. I love speed, but I'd buy the IS f4 version over the f2.8 non-IS lens anyday. I'm really sold on IS for lenses at 200mm and beyond. I think that IS isn't as useful on a short focal length lens.
Shawn