Since Mentalists get by on their personality and not the effects they do, your question is moot.
Derren is a very skillful up and comer but then again there are also many others that have as good style and technique. Max's performances not only contain only original material but also his persona is one that really cannot be duplicated. There is only one Max. Darren is a very creative thinker as well but there are others with as much skill and creativity as well as stage presence. Marc Salem, Craig Karges, Banachek, Tim Connover, David Berglas, come to mind right away and I could list at least a dozen more that belong up there too.
If you want to compare creativity, Max Maven will undoubtedly go down as one of magics greatest innovators and thinkers. There are very few people I can think of that I would consider a brilliant showman, great magical thinker as well as a walking encyclopedia of knowledge and Max is one of the few not to mention a very cordial gentleman. I have always enjoyed discussions with him as they are always full of useful insight.
Paul Alberstat http://www.mindguy.com