Commencal riders are on fire: Amaury Pierron has won multiple World Cup races, and Myriam Nicole is the reigning DH world champion.
The question is, are commencals well-suited for the beginning recreational rider or even average rider? A combination of 29" wheels, long travel, and reputedly one of the fastest rear suspension designs around, could get a rider with modest skills into trouble very quickly. You could find yourself riding relatively smoothly through technical sections with much more speed than you normally would, and if you push a little too far past your skill level, well....
Also, commencal and most all longer travel bikes will not pedal as well uphill. If you are out of shape as a beginner or weekend warrior, these bikes could tax you more than a bike with more modest suspension travel.
I've had so much fun riding 140/140 bikes: I think they are a nice balance point between xc bikes and dh, but I don't know, a 160/150 commencal might change my mind. Hopefully I can hop onto a demo in the spring.