Only real problem with it is the fact that you have to have both ends of the light on to use the LED
Actually, this is not quite right. Yes, you use the twist-head of the Mag to activate the LEDs in the tail cap- and you need to have an intact bulb in there in order for it to work- but when set to either LED mode the main bulb does not light. The current flowing through it is too low to make it even glimmer.
You twist the tail to select modes- from red LED to white LED to Main Bulb, and turn it on/off with the twist-head, regardless of mode.
White LED is OK, nice colour, it`s brighter than my Infinity and dimmer than the Arc AAA but certainly useful. Red LED is dim and full of rings. Also, oddly, it consumes more power than the white one despite being so dim! Still, for preserving night vision, or maybe signalling(?) it`s useful.
I find it to be a useful accessory. Note, it doesn`t work with the Opalec NewBeam module fitted in place of the Maglite`s stock bulb, which is a shame. I tried it and just got a dim glow from both ends, nothing too useful.