Excerpt: I bought a kit that included this lens with a T2i body, my first adventure in the DSLR world. It's given me a taste of what the higher-end lenses have to offer. The auto-focus is quick and definitive, image stabilization enabled me to start taking solid photos right out of the box. Mode II works well for tracking subjects against a busy background, for example a bicycle race. The build seems a little light in some respects but the lens functions well.
Conclusion: When I purchased my 7D, I also picked this lens up for some wildlife and nature photography. With the cropped sensor, 300mm is close enough for animals that don't want to eat you... I'm impressed. Images are pretty sharp and colorful. The image stabilization works well, for the most part, and focus is usually spot on. The build quality is very nice, for a non-L. It's plastic, but it's solid plastic. The zoom ring feels nice and is just the right resistance.
Pros: Superior build quality, Super-sharp images, image stabilized