Well, took the plunge and ordered the NX300 with the 'kit' 18-55 mm lens and the 16mm pancake lens.
Very nicely built, solid feel. The lack of a viewfinder takes a bit of getting used to, but the rear articulating touch screen is excellent. Rotate it up and its a bit like using a MF camera! Touch focus is pretty cool too, tap the image on the screen and the focus sets to that point.
In a quick test of the kit lens against an older Nikon 18-70 on a D7000 indicates that the lens has very good center resolution, but some decentering at the top left of the image at the widest setting. Haven't really compared the 16mm yet but it appears sharp across the whole frame. Color balance is quite different than the Nikon. Generally the images seem to be as good as the D7000 / 18-70 combo, which is in my view quite an achievement for an almost pocketable compact.
So far a positive verdict and fits the bill nicely for a camera that can be used when lugging a DSLR around is impractical. I'll try and post some comparative images after I get a chance for some more serious shots next week.