Oh snap... 
  
Point Jens! 
  
Personally, C4 destroys all other rubbers (both 5.10's  Mystique and Onyxx, and Sportiva's various vibrams)...that is my opinion only.  I've used it so much i know exactly what to expect and my confidence is high...  Predictability if you will...Your mileage may vary. 
  
Jens is a sportiva guy so he probably is doing the same thing as me...he likes what he knows...