Just got a new G1X this evening and have been playing around with it, in very low light (it's almost winter here in Australia).
I've been pleasantly surprised about the speed of the focussing, compared to some of the horror stories I've read about it.
It's not as fast as my 60D, but it only takes a half a second or so to focus in low light, which is pretty good for a P&S.
The high ISO is pretty good too and probably better than my 60D at 1600.
The built-in flash is amazingly powerful too.
I took some videos of one of my cats under very poor light, and the video came out surprisingly well and it plugged into my Samsung HD TV and the TV automatically switched the source to the camera as soon as I turned the camera on, and the video looked pretty good to me.
I'll play around with it over the weekend to see how it goes when photographing something decent, but so far, I'm a happy camper.
Funny thing is that the retail price of it here in Oz is cheaper than it is from B&H.
A$749 as against US$799, but I got it as a grey import for A$650 delivered from Hong Kong.