I had a test ride of a Specialized Enduro. I found it was neither light nor a good climber. Compared to a light xc hardtail it is an absolute pig to pedal uphill.
I always thought Spesh stole the name from the motorbike enduro races. Paris-Dakar kind of thing but only for motorbikes. The bikes tend to be a mixture of MX/road machines and designed to ride over everything.