I ended up with the 650 instead of the G9, but as I understand it, they are about 90% similar, especially as far as image processing (except RAW on the G9) and controls. After reading about Canon and RAW files, I decided I didn't need that option. I think the other main thing I've given up with the 650 was some of the custom color options that Tech posted for his S series Canon:
http://www.tfproject.org/tfp/showthread.php?t=125860
The toss-up between these two came down to the comfort of the camera and need for RAW image processing. The 650 has a better grip handle and I decided I could do without the RAW since I'd never had it anyway. Having the flip-out LCD is nice. Both cameras had a good heft to them, which I think is better than having something super-light.
For the little bit that I've used it, I've enjoyed it. It seems there will be some features I'll probably never use such as the 3200ISO and their special "postcard" resolution.
When I was taking the photos above, I did notice there were times the camera had trouble finding its focus. If I was in macro mode and zoomed out, there were no problems. When I tried to zoom in, the camera couldn't focus. So, most of these pictures are at wide angle and I just moved the camera in until I got the framing I wanted.
There are many direct comparison of the 650 and G9 on dpreview.com.