I put off this purchase for a while. Now that I have it, I wish I'd bought it a long time ago!
What an awesome lens this is! All the reviews on here are accurate (thanks for posting them). I've used it on a 10D and 30D with great results. I shoot a lot of low-light, no-flash action photography and needed something in this range (136mm with DSLR's extender) with a large aperture. My Sigma 70-200 EX is on 80% of the time, but at 2.8 I can't always get the shots I want in those low-light - no-flash situations. I dream of a 70-200 f/1.8!!! What a jewel that would be!