Here are two snaps from my DP2-S, which I haven't been able to use as much as I'd like.
RAW files do take 5-6 seconds to store. Haven't tried JPEG's yet to know if they take less time.
There's an option in the DP2-S, and I think in any earlier cameras upgraded to the current firmware, to stop the autofocus from searching in the first meter. This both speeds up the AF and makes it a bit quieter. In either case, the Sigma's autofocus is considerably faster than my manual focusing, on any camera.
These were loaded into Sigma's software and then saved, with no processing. I may have cropped them; can't recall.