I have had the SD9 for about a year now and get on with it very well.
The drawbacks are;
(i) its greedy on batteries, you would need several sets of rechargables.
(ii) You have to download to the computer using Sigma software, and compared to the 'others' may seem a bit long winded in the first instance.
On the plus side;
The Sigma Photo Pro software I find very good, its possible to adjust Exposure; contrast; shadow; highlight; saturation; sharpness: very easily and with immediate effect. And would take much, much longer using PS
The resolution is exellent, unless you want to print large size pics, you can leave the camera on medium which produces very good A4 prints
Any further questions feel free to ask
_________________________