Even in relatively low light, I managed several nice shots with this lens, along with my Tamron 70-200mm f2.8 and Tamron 17-50mm f2.8 zooms, which are nice fast zooms, although I have lens fever now that I've had one of Canon's USM lenses in my hands - very smooth, fast focus.
I plan on using this lens on an Idaho trip next weekend. We'll be up there visiting family and spending 5 days in the Driggs, Idaho/Grand Teton area. This lens will be great for some long reach when we various birds and wildlife.
On to the pictures, hope you enjoy!