Me again, I finally found some time to take a controlled photo using the SD200.
The example photo was taken at iso 50, no flash, somewhat lengthy exposure (there's no actual way of knowing), tripod mounted, widest angle of 35mm, tungsten white balance. Light curves adjustment and sharpening applied. Camera was set on "low sharpening" mode.
I took this shot to help emphasize edge softness, barrel distortion. Unfortunately, I can't use it to judge vignetting because of the light in the room.
I tried to draw a straight line to show you the amount of barrel distortion in the image. It's usually worse at the very edge by I like to know how it is closer to the center.
You can see that barrel distortion is acceptable (most people never notice it) and the software at the edges is a little strong (somewhat less acceptable compared to most zoom lenses of 35mm on a DSLR). But that's what you get with a point and shoot.
I think this camera performs VERY well optically at it's wide angle setting which is probably where I'll be using it most.