My usual workflow is to upload pictures to Aperture then edit them in Photoshop if necessary.
First I was disappointed when I saw the pictures in Aperture because of the posterization (worse in this picture than any others, but still visible). So I compared the pictures I had just uploaded to those on my LCD screen, and the transition between shadows and light is perfectly smooth on the LCD - even when I zoom in! When I started editing the images in CS6, it was worse than in Aperture...
What am I doing wrong here?
Nikon D610 - RAW
The following example (potentially NSFW) is a JPEG of course (mouse over to see the image)