Unfortunately, the GRD2 JPEG NR seems to be a serious problem. Yes, it affects only the people who uses JPEG. RAW is just RAW without any (known) prostprocessing. But because the Continuous and Bracketing modes are not available in RAW, some of us photographing in RAW are from time to time forced to use JPEG. And here is the problem. Look at these crops:
As you can see (in the first row), we are now suffering a serious color bleeding, so familiar from the Panasonic cameras. See for example this older (but still valid) GX100/LX2 comparison, made by Bjorn Utpott:
Yes, the GX100 is noisy, but hey! There is not even a single trace of color bleeding and any other strange NR artifacts even at ISO400! Unfortunately, the same cannot be said about GRD2 JPEG files, and what's worse, even at ISO100! One would expect white letters from RAW to be white also in JPEG. Unfortunately, it's not the case of GRD2 JPEG. And It's definitely not a problem of red/white color combination. I can see the same problem also with other colors and on many other JPEG shots. See for example this GX100/GRD2 JPEG comparison:download/file.php?id=706
And this is, I believe, a serious problem! I would not expect this performance from a high class camera! Not to mention, the problem is not present in GX100! Simply, the new GRD2 "smooth engine" is just the same evil as the "famous" Panasonic's "Venus III" engine. But while the Panasonic is known for playing a dead horse and ignoring their customers, I really hope Ricoh will listen the voice of customers and allow us to turn the NR completely OFF. Just one little additional switch and we all would be happy again.
The second row in above example shows another weird JPEG behavior, which I'm not quite sure it's NR related. There seems to be lost or significantly reduced some colors. It may be caused by a NR or JPEG compression. But my personal tip is that it's caused by a chromatic aberration removal procedure, which is apparently done over the JPEG files. And I have to say, it's quite effective on some kind of chromatic aberration colors! Unfortunately, in many cases it appears to be too effective and removes also "correct" colors.