Quite late addition to the discussion. FWIW, I've run an AXA since LEL 2013, where it was brilliant (and reliable) and kept me, and various electricals (Garmin, phone etc.) running very well.
However, it's recently been less reliable, with (in particular) the charging being intermittent.
So, I upgraded to a Luxos U, which has a brilliant beam-pattern, but I seem unable to get the hang of the switching or, FTM, the charging, where I've yet to get the "charging available" light come on at all !
Now, I've not give it a good "shake-down" ride, where all may become clear..........but I'm tempted to carry the AXA as a (mostly) reliable spare,........seeming to defeat the object of upgrading (doh !).
"the only constant is inconstancy"