I have a G10 with the Canon underwater housing. The case is very well made, but the G10 is just too slow under water. The autofocus is average above water, under water it gets real tough to achieve focus. There is a long learning curve until you figure out how to use the combo. My biggest complain is just that due to the camera having such a hard time focusing, you miss a lot of the action under water. However, I do have a few beautiful pictures, but most of them are lucky shots or "scenery" shots. The G12 may be better in the focussing department, and that would help tremendously.