The Coolpix 800 shares its CCD and internal image processing algorithms with the Coolpix 950 and it shows.. Image Quality is very good, some slight noise but very good definition, excellent exposure and white balance... In fact many is the time you point the camera and press the shutter release half expecting a bad shot only to be "impressed once more" by what the Coolpix 800 turns out.
The comparison below compares the 800 with the S10 and these shots were originally used in my Canon S10 review.. I'd still have a tough time choosing between these cameras.. The 800 has a better "in your hand" feel, faster operating feel (notice I put feel because they're actually as quick as each other, but somehow the 800 feels as though it's recoiled quicker) and a more robust outlook on photography.. The S10 is a looker and has some great features.
Compared to the Canon S10
General observations: The S10 shows better clarity, is less affected by colour boundaries and shows little or NO noise, this is especially noticeable on the image Crop II which is a crop of the reflection of the Martini bottle on the Martell bottle, the Coolpix 800 shows noticeable "shadow noise" which is to be expected of any digicam in such low light, the amazing thing is the S10's ability to not only deal with the low light but also pull more detail out of the shadow.