The custom grip for my Canon G9 arrived today. It definitely improves the feel of the camera.
The grip itself is heavier than I was expecting, but then again it is a solid piece of metal. The G9 is a very hefty point-and-shoot anyway though, so I wouldn't call this a real problem. It does seem like the all-metal design will suck the heat right out of your fingers in winter. On the flip side, the grip vastly improves handling when wearing gloves; it no longer feels like it's going to slip right out of you hands.
I am impressed with how well it fits the features of the camera's body, right down to a slot along the edge to accommodate the existing rubber strip/grip. The texture of the grip is also less course than I was expecting, but it seems sufficient. I was also a little surprised to discover that the grip is held on with very strong double-sided adhesive tape. I guess I was expecting it to latch on mechanically in some fashion.
In any case, if you're planning to stick with your G9, I recommend this little upgrade.