I have a G10 and I love it... within limits.
It is good for landscapes and outdoor scenes in good light. If you can stay at ISO 100, you're fine.
The optical viewfinder is worse than useless. This bothered me at first, since I have almost always used SLRs or view cameras. But once I realized I could brace the camera using the neckstrap and use the lcd on the back, things were much better. This is especially important for closeups, and the G10 does amazing work on things that are absurdly close to the lens -- but only if you frame correctly (the optical finder is useless for anything closer than ten feet or so.)
When I don't want to lug around a tripod and my 5D, it lets me get shots that I would otherwise miss. And image quality (at ISO 100, in good light, without too great a contrast range, with subjects that aren't moving around too much, etc., etc.) is excellent for prints up to 13x19".
Thus, within its limitations, it's a fine camera. But you can't expect good results at high ISO. It's no substitute for a good DSLR.
That's my take on it.