I just got an M6. /ubbthreads/images/graemlins/smile.gif I haven't played, umm -used- it much yet, but I like it so far, solid construction, white light, decent throw and light output. It's not a throw or output monster, but it is decent. /ubbthreads/images/graemlins/thumbsup.gif
I can't compare it to an X0, but I did a quick comparison to an Arc4 and a tweaked PrincetonTec 40 (Mag 4-cell xenon bulb with 4 NiMH cells). The M6 has a bit more output than the Arc4 (as expected, ~40 lumens vs ~30 lumens) and a bit more throw (bigger reflector than the Arc4) and a bit less output and throw than the PT40 (which I think is running around the ~60 lumens mark).
For EDC and indoor usage, the Arc4 still wins. As an outdoor walking-the-dogs light, the Arc4 is a little too little (in size, output, and throw). The PT40 with the xenon bulb and NiMH cells is a good outdoor light, bright with decent throw, but not blinding for the user. I still have to see how the M6-LED is for a walk-the-dogs light.
The PT40 will light up a house 100 yds away enough to see and ID things, while the Arc4 doesn't quite reach that far even on Level-1 (the beam is a bit too diffuse). The M6-LED reaches the 100 yd house, but a bit wider on the hot-spot than the PT40. The environment is open suburbs with a goodly amount of light pollution from porch lights and strteet lights. In close quarters in more dark areas (hiking a trail in the woods, for instance), the M6 might be a bit too bright for close-in usage and the PT40 would almost certainly be overkill close-in (closer than 10-20 yards).
In true CPF form, get them all. /ubbthreads/images/graemlins/smile.gif