Interesting chart --- esp the Reasons to buy the Canon PowerShot G10: High true resolution, 14.6 MP, Great macro, etc
Raises the question, why compare the G10 to the G15 instead of the G11 or G12?
For firsthand insight check out the image comparison tool at DPR: call up the G15 review and select the G10 from the camera model comparison list. At the top above the main image you can then change JPEG/RAW and ISO and do some pixel peeping. Here's the link but I don't know if it will work fully http://www.dpreview.com/reviews/canon-powershot-g15/11
Canon, or any other maker, it comes down to knowing your specific needs.
borderlight nails it perfectly: personal preferences --- which also helps explain why G10's in top shape sell so fast and are often so darn expensive for a five year old P&S.
I have a G10 and upgraded to the G1X but mainly still use the G10.
Lots of reasons, just a few being build quality, size (it slips into my pockets easily), superb lens, sharp images at A3 size (amazingly sharp), As I use my cameras in normal daylight I don't need to exceed ISO200........but I do go to ISO400 if looking to do B+W...the results are close to a fine grain film.
The G1X is better in some respects particularly ultimate image quality...but not so convenient to use in my opinion. Looking back.....I wish I had saved my money or got a Fuji X10 instead to play with!!