I've used it with CNX2 2.2.7 and earlier versions. It works fine. Because NX Signature generates a colorize step you can easily change the color of the watermark to blend with your image. I often use the eye dropper to select a color from my image for the watermark.
A couple of caveats to be aware of:
You can only specify the coordinates of the watermark in absolute terms relative to the upper left hand corner of the image. This makes placing watermarks in the bottom of an image or having it right justified impossible unless all your images are the same number of pixels. Also switching between landscape and portrait orientation makes any position other than the upper left of the image impractical.
The pixel size of the watermark is fixed. This means that you probably want to apply it to your image before resizing so that it overlays the same portion of your image regardless of the final image size.
Gary in SE Michigan, USA. Co-organizer of the Southern Michigan Chapter Nikonians membership - My most important photographic investment, after the camera. D4, D800e, D300, D90, F6, FM3a (black), FM2n (chrome) YashicaMat 124, Graflex Speed Graphic 4x5 My Nikonians Gallery & Our Chapter Gallery