I agree with Eric 100%, but I would be doing this community a disservice if I didn't write my heart out. Below are things I discovered in the last two months of M6 ownership....
Since the lens up front is plastic, and plastic prevents some of the light from the reflector from bouncing out of the front, I highly recommend a glass lens as a replacement for both durability and more complete transmission of light. Flashlightlens.Com sells a 29.1mm glass lens, that is anti-reflective (AR) coated on both sides, in either a 1.2mm or 2mm thickness. The theory is that uncoated glass reflects some of the light emitted from a reflector or optic, back to the source. This light cannot be recovered. With an AR coated lens, most of the light passes through the lens and goes out the front. This is what we want from all of our LED light sources.
The reflector, although it looks the same as any other one, is probably the best component in the M6. They are used in modifications of lights that can accept this size. The coating is somewhat dimpled, to smooth out irregularities in a light's output. It is deeper than most reflectors of this size. Of course, an LED has very few artifacts compared to an incandescent lamp such as is used in the M6 Lithium light.
Those who want to get the current version with the rotating head for fine tuning the beam, better do so fast. The next round of the M6 will have a fixed head. Since the beam pattern can be adjusted in the current version, one can see a difference in the light when the bezel is turned from one extreme to another. You won't see a big difference. But play with it to get it right for your needs.
Although the hard anodizing is industrial grade and not Mil-Spec type III, it is a tough finish. So what if you can't cut through concrete, with it at the end of a jackhammer!!! Just use it as a lighting device, and you will be fine.
The tailcap switch is a clicky with "momentary-on" and "stay-on" functions. Even the feel of the switch can be adjusted for a lighter or heavier touch, by rotating the tailcap in or out. I was advised not to turn the tailcap all the way in. In this position, the brass rod pressing against the battery's negative terminal is exerting the greatest force on the battery case, and if the light is dropped on it's end, the rod could conceivable dent or puncture the battery's thin wall. Yes, batteries have thin walls to save on the cost of metal. So adjust it the way you want, but make sure that it is backed out a little.
With regards to the human touch, the bezel and tailcap have an octagonal shape, to prevent it from rolling away into someone elses hands, and the middle of the body has a very fine diamond knurl pattern, to help you grip it. The Cordura holster with a strong snapping clasp, as well as the supplied two CR123 batteries, don't hurt either.
I cannot imagine anybody not liking this light for it's quality, features, and low price. It is not a lightweight, but it is worth "hauling" around with you.
Luxlover out!