Overall, I'm quite happy with the lens so far. From the set of the flowers in a high contrast shot, it was reasonably sharp at the center wide open, and the CA isn't very bad (you can see it at the edge of the flower pot in the lower center shots).

When driving home in heavy rain yesterday evening, I saw some trees that looked great. I pulled over to the side of the road and took a shot through the car window, in the rain, at dusk, on a cloudy evening. I shot at different zoom settings, and at 1/20 to 1/30, f6.3 and ISO 1600. This was a pretty good test of the IS.

The third set of the house shows that the focus is pretty good across the whole shot, although the house shows some CA and the door shows some barrel distortion. All in this set were at 17mm f4, with no sharpening at with Parameter set 2.

The last set amazed me: hand-held at night, at 1 second and ISO 3200. Yes, there's lots of noise, but the photo is pretty sharp for hand-held!