You can see the differences such as weight and torque on paper here:

http://www.fittingworks.com/TechnologyProcess/ShaftandGripInformation/ShaftDescriptions.aspx

It's always difficult to explain the goal of each shaft with so many variables between players, so you definitely need to go through a fitting and see how they work and feel.  What I can tell you is that the Diamana Branded shafts are responsibly for a majority of sales where as the Voodoo is no where to be found. So you can join the party or be a one man wolfpack.  ;)

Ryan Crysler
Head Instructor
My Golf Performance Center
512.850.5721
mygolfperformance.com

Its mostly user preferance. The Voodoo is a little heavier shaft. the kick points are mostly the same and launch angles are the same also. Voodoos have a tendancy to play stiffer than average based on some of the coments i've seen in the past. Shaft selection is a fitting option that Fitters can use to help you gain the best out of every club.