I've had the G9 for a month now and I really love it, I use it more than my D-SLR now because of it's portability. Image file size is huge at 12 MP you get a lot of pixels to play with. Recently I took this camera along with the underwater housing canon makes for it and it does great. You can program 2 custom functions for underwater photography, one for open water settings and one for macro settings so all you need to do is turn the control dial and things are ready. Taking the camera in the waves to photograph some body surfing took some getting used to, due to the slight delay in the shutter, but it still is the the shortest for PS cameras. Sitting on the beach and using the digital zoom to catch surfers did well too, pixilation is just noticeable.
This little camera is for any photographer that likes to have a useful camera wherever they are. 1600 ISO and 3200 program mode allows for taking photos in any lighting situation. At the higher pixel count the pixels look more like film grain at higher ISO. RAW image files are huge and you can make custom adjustments to your images easily. 2 custom white balance settings make it convenient to do a white balance setting for your particular light for your tank and save that setting so you can always use it to see the progression of color intensity of corals as the grow over a length of time. Than use the other custom WB for other things.
Handling is a little bigger than most PS cameras, but it's just big enough to be considered a real camera, has a Leica feel to it. Solid camera my wife dropped it about four feet, and with a thud it landed on a corner. The corner was bent up a little, but not broken so I guess the magnesium body did it's job. It's just big enough to put an external flash on it. Bouncing the flash indoors yields excellent photos.
There are also nice auto features too, underwater, fish tank, 2 fluorescent light settings, sport mode, portrait, pet mode, haven't tried that but sounds interesting. So far I've used this camera for trips to the beach, a family funeral, a nephews birthday, shots of the aquarium and random photos around town. Just about the perfect point and shoot as you can get.