Conidering the reviews this lens gets, I found it quite difficult to find anyone who actually has one. Don't know if you'll find it useful but this is part of a reply I got to an enquiry to an owner on another forum last year when I was trying to decide between the 100-300 and the 70-200:
"This is a SUPERB Lens. I absolutely love it and would probably only get rid of it for a Sig 120-300 2.8! Buying from scratch I'd say it's a VERY tough choice between the Sig 70-200+1.4 and this one. Both are superb (although I haven't tried the 70-200 yet)
It kind of depends what you plan to shoot. For my use so far I have had no problems with either f4 or handholding. Its heavy but well balanced. But it could easily use a mono or tripod.
Yes, it comes (like all EX sigma's) with a superb case and hood and this comes with a removable tripod mount.
I, personally, am no fan of Canon lenses, so consider me biased, but I don't think you can go wrong with the Sigma Tele zooms, and probably, for the money, the 100-300 is the best."
His site can be found
here for examples.