You should forget about the Optio S and start looking at the Optio S4i.
The Optio S in out of production and the 4 megapixel S4i is taking its place. You will find that the S4i is probably cheaper than the Optio S.
Pentax has had a year since the Option S to correct problems. The S4i should be better.
Here is a link to a side by side comparison:
Look at the chart for the S4i. Look just under the red stars. Click on "read owners opinions" and you can read what real owners of the camera think about it.
I am seriously considering getting the Pentax Optio S ALMOST solely for the fact that it is SO small that it can fit in an Altoids Tin. I am SICK of carrying around a bulky camera when I go out. The Optio S seems satisfactory, but after reading so many reviews, it appears that the Optio lacks in image quality (purple haze, blurry edges, noise at night etc) Are there any other small 3.0MP+ cameras that are small enough to fit in an Altoids tin? I really want the camera to be as small as possible but still take good pictures. I know it's give and take and I can't have my cake and eat it too but I figured I'd ask if there are comparable models that I don't know about. THANKS!