I too thought the images were a little soft. Hard to say, though, that could have been the lens (!?).
It did strike me though that the higher ISO images were better than the images posted on the Japanese site mentioned in a thread a week or two ago, especially at 400. The dpreview images had much less noise than exhibited in the images on that earlier site. That said, the noise, while reduced, appears to still be present at even 400 ISO. With NPZ being as good as it is (at 800), it seems one of digital's achile's heel still seems to be high ISO and long exposures.