Thanks for the kind words, I'm really enjoying the lens!
Anewman - It does focus faster than my other zoom lenses (18-55 kit that came with my Rebel XTi, and the 75-300 USM III which is not noted for its speed), and is pretty comparable to my 50 mm 1.8 speed wise. I snapped a few of my daughter on the swing, and it was pretty quick to focus.
Jann - I haven't had any problems with the focus hunting, and I did take some shots at a retirement lunch indoors the same day I got the lens (it helped me justify the purchase in my mind

plus I needed to practice before our upcoming road trip

) and I found it very quick in low light conditions. The macro end is 1:2.3 with a minimum focus distance of 20 cm. As my son would say sweeeeet!
Tinksdad - Thanks! I was actually surprised with the bokeh on this lens, as I hadn't seen anyone comment on it in reviews. As for DC, here is the blurb from Sigma's website:
DC (DC Lens)
These are special lenses designed so that the image circle matches the smaller size of the image sensor of most digital SLR cameras. Their specialized design gives these lenses the ideal properties for digital cameras, the compact and lightweight construction is an added bonus ! including compact and lightweight construction.
Can't wait to take some more pics
