Bit of a thread rez but I didn't see current measurements on any of the reviews, and that 2x the runtime for <1/10th the light seemed suspicious.
With all tailcap current measurement caveats in mind, I get: 670, 160, 20mA for an estimated 800mAh runtime of 1:10, 5, and 40 hours. So L may be less efficient than M but not as bad as the spec. 5h makes much more sense for M than the 25h claim.
The Nichia version of this has a lovely tint, and is a great upgrade from my Inova Bolt 2AAA in performance, even if it doesn't look half as cool.