I bought a Canon G10 two days ago, and haven't had the time to really put it through its paces yet...however, I've formed a bunch of initial impressions from a couple of shots made in the streets of New York. I will follow up with further thoughts as I use it, and will post these on TTP. I suspect that many of my eventual thoughts, if not all, will mirror other comments made about the G10.
First and foremost, a no-brainer: this is not a DSLR...it's a point and shoot. This fact was reaffirmed to me when I walked over to the DSLR counter at B&H, and was directed by the guy to walk to the other side of the store...to the point & shoot department. So if you expect DSLR quality from the G10, think again. It may come close, but that's about it. Will it replace your DSLR? No. Will it be a back-up for your DSLR? Again, probably not...but that depends on what your definition of back-up is. For me, it won't be.
Secondly, the shutter lag is noticeable. In the above photograph taken while crossing an avenue in New York, you'll notice the tip of a vehicle in the bottom left corner of the frame. This appears because of the shutter lag...the vehicle wouldn't appear had I used a DSLR. I shot this frame at 25mm, f4.5, 1/200th, and an iso of 80.
The quality of the image and color rendition are fine, although still not as good as from a large-sensor DSLR....okay, since you got the message by now, let's drop the comparison to DSLRs since it's really comparing apples to oranges.
The size of the G10 is ideal for street photography (which is the reason I bought it in the first place), it's easily portable in a coat jacket and it's easy to use out of the box. I don't think the G10 will be great for active people photography for instance. I'm quite sure it wouldn't do well at the dance festivals in Bhutan...but it could be very useful in posed environmental portraits.
To be continued....