I really have not had a whole lot of shooting time with the new itty bitty camera yet. Too distracted with other things. Maybe I'll make it out of the house this evening. Of course I have snapped off a few stupid ugly shots of nothing just to see how it works. I can tell you that I have no hesitation shooting this thing at ISO 800 and not much at ISO 1600. Higher speeds are more of a must have the shot at all cost affairs - they are not wonderful. On the other hand if I shoot them with the grainy black and white "art" filter that people seem to like so much who cares, you can't tell what ISO they were shot at. I will probably use that methodology in real life when forced to shoot at 3200 or 6400.
As for low shutter speeds. I can say I also have a lot of confidence in the built in image stabilization. It works at the top is a shot that wasn't particularly carefully shot. It was at ISO 800 1/6 second f 4.5 or thereabouts - the focal length was equivalent to a 50mm on full-frame. I don't even remember where the camera focused it was on "choose for you mode" 1/6 of a second after about 9 coffees today, holding it with my arms extended shooting downwards vs against my body. I would say the image stabilization works pretty darn good. This JPEG is resized right out of camera with all of the settings "flat". All things being equal my next lens is that Panasonic 20mm f/1.7. This thing is fun.