Also, I forgot to mention.. I did some tests myself at ISO200.
Nothing I care to post just yet, but I think if you leave the NR on
STND you get a better result for the companion jpegs. Set on HIGH
you get that "water color" NR effect people complain or, and if
you're on LOW you see too much of the jpeg artifact. STND seems
about right. And, if you shoot RAW ISO200, kick your luminance and
color noise reduction up to around 80-90 percent, sharpening to
zero, in ACR 3.2, then smart sharpen (CS2) afterword in PS, you get
a VERY usable ISO200 image.