A few days ago I ordered this Canon lens. I currently have a XTi with the kit lens and the "nifty fifty" which I picked up a few weeks back. My goal was to get a decent lens that I could use to replace the kit lens while getting a little more zoom at the same time. However, I today I saw this lens for $20 less. The extra money isn't that important to me but I was wondering if the sigma is an overall better lens. I plan on using the lens for sports and some outdoors/wildlife. I know that both of those lenses may not be the best for either of those two things, but since I'm just getting started I didn't want to put a lot of money into a single lens until I was really comfortable. Any input would be greatly appreciated.