I like it now very much but before I could make it work I had to learn or discover certain things.

1. It does not display in preview accurately.

2. In most cases it should be set at a relatively low intensity if used with other lights... under 50%

3. It can be used at full intensity by adding an "edge blender node" to the light in the material room or by making the diffuse color of everything in the scene a middle gray under their textures.

4. It works best with ambient occlusion added to the important surfaces in the Materials Room.

I think those are all the main things to remember.