Hi Russ
I just got my G9 to replace my A640. I used to have the Canon lens adapter for the A640 but it fit very sloppy and and seemed fragile. I then got the Lensmate and it was a world of difference, for the better. Fit tight and was solid.
I now have the G9 + Lensmate. The adapter fits very snugly and is very high quality. I use it for my Oly TCON-17 tele via a 58-55 adapter ring (500 mm with 1.4X digital zoom!!!). Like others, I also use a protective filter on the lens mate when not using the TC.
For full time use of Lenmate:
Pros: 1)Significantly improves the handling of this P&S for someone like me with big hands. You can grab onto the barrel of the adapter and help to steady your shots.
2)Protects the lens
3) ???? MAYBE protects against the dust problem of the G7 (this is VERY questionable)
Cons: 1)At full tele the lens will hit the back of the filter attached to the Lensmate, so you have to either restrict the tele by a tiny amount or screw the filter out a turn and a half (then duct tape in position
2)Its not longer pocketable
3)Vignetting with the flash at wider angles
4)Obstructs the OVF some
Hope this helps!
Les