I also have an M10 and an M7.
1.)The M10 switch is slightly different from the M7 in that the M10 switch is kind of "flush" with the barrel, where you have to push your thumb into the barrel to turn it on. The M7 switch is much easier to use.
2.)The 40 Kcp listed on the specs is kind of misleading, IMO, partly due to the very tight beam pattern. My Magcharger with 40 Kcp bulb puts out a heck of a lot more light, as does my Mag 2C with 3x123 and 6 cell Magnum Xenon bulb, and any of my 2x123 mini lights(SF 6P, SL Scorpion, Pel M6, Brinkman LX, ASP Triad, SF Nitrolon). I do have a piece of WriteRight on the lens, and it cleans up the beam a bit without a really noticeable loss of output.
It is a decent light for the price (I got mine for about $30); I kind of disagree about the aesthetics of the light, as I don't find it to be a very "nice looking" light. The switch is kind of high up on the barrel (close to the head), making overhand carry cumbersome. The material of the light makes it difficult to carry in the pocket (sticks to your pocket), and the smaller head does not allow use with the traditional "D" ring holsters.
Hope the info helps. /ubbthreads/images/graemlins/smile.gif