I have this with the 5 mode XM-L T6 led in it, and it is VERY BRIGHT!!! (the equivalent of a 1M candlepower spotlight or a 40W desk lamp) But after a few days playing with it, it started to jump between modes, dim out, flicker etc. occasionally, it would cut out completely Well, I read somewhere a dieing battery causes it. this is not the case. However it does appear the amount of charge in the battery has an impact.
so, me being, ME, I decided to tear apart the torch and diagnose the problem. I looked at the drop-in module... that wasn't the problem. I turned my suspicion to the switch. It seems this was the problem, so I looked around for a replacement, no luck.
my next challenge was to find out how to take apart the tail cap to get to the switch itself.