I bought this camera to supplement my Nikon D50. There is no question that the Nikon takes better pictures but it costs twice as much and you can't slip it in a pocket.
The pocketability factor is the big draw for the Casio. The S600 is astonishingly compact, about the size of a credit card and about a third of an inch thick. You can stick it in a shirt pocket and carry it about without knowing its there.
It also takes great photographs as well. The colors are not as good as the Nikon and it does not focus as well but they are better than any previous compact point and shoot digital camera I have used.
The Casio scores very highly on the other two points that are important to me: shutter lag and battery lag. For years I used to read reviews in digital camera magazines and wonder why they never mentioned the single biggest drawback to the cameras they reviewed: they would take a second or more to take a photograph after you pressed the trigger. Forget taking pictures of children or at a party and there was no hope at all of getting a picture of a moving subject.
The reason the reviews didn't mention the dirty little secret of the digital cameras of the day was they were all terrible and they didn't want to scare off advertising. The recent generation of digital cameras have changed all that. They are true point and shoot cameras, not point, press, make a cup of tea, drink it, pour another one and shoot cameras.
The other dirty secret of the earlier generation was that they sucked the life out of their batteries so fast Dracula would have been impressed. This made me a little nervous as I slotted the thin Casio battery into the Exlim. It's not much to look at, not much thicker than the SD memory card. And just to make you a bit more nervous about running out of juice the battery has to be plugged into the camera to charge.
Don't worry, I have taken a full 1Gb SD card of pictures without even having to think about charging it. Each 1Gb card givesw 350 high res, high quality shots or so. There seems to be little point changing the settings unless you are really pressed for space and with the 2Gb cards now selling for $50 that isn't very likely to happen.
The Exlim certainly can't compete on quality with the digital SLRs but it can certainly put in a respectable performance and certainly hold its own against other $300 cameras. Where it really scores though is in convenience, in that area it is absolutely flawless and (so far) unmatched. If thats what you need buy it.