Shooting some neutral gray object can be of great help for getting the white balance (gray balance) in your RAW converter right. We discussed some options here.
The new Datacolor Spyder Cube is a new tool in this scenario:
This little tool is quite sophisticated and offers some new options to get the exposure right.
The right way to get the white balance right is to click on one of the gray sides (not the white).
Because the two gray parts face to different sides you can select the side that is more directed to the main light (e.g. sun). A normal gray card would not show this difference.
Whether this matters to you is a different thing. Clearly for shots in the studio it can be very helpful while most nature and landscape photographers are often happy getting a more subjective white balance. On the other side even for subjective white balance it may help to start with a correct reference.
There are also some other Spyder Cube features that can help you to improve your exposures.
The truth is that the white on any card can be darker than the brightest part in the scene (specular highlights, surf, chrome reflections). Here the little silver ball helps to show some specular highlights. This way you have a strong highlight reference to test your exposures.
You may think that the black painted side of the cube is black (or the black of any other card). Then look at the black trap (a hole shows the black painted inside of the cube). Now we are talking really black. Again it can be very helpful to have this kind of test reference in the scene.
The cube is pretty small but not quite as handy as a WhiBal.
The new Spyder Cube is an excellent tool for getting optimal white balance and very fine tuned exposures. Overall a great concept.
You find more information on the Datacolor website.