After using this light for a few days, I have a few observations. First and foremost, to like this light, you must be willing to accept some compromises. These include:
1. The smooth (best throwing) reflector is not the prettiest, to have the best beam you have to use the OP reflector. Until a new reflector is designed, this will never be the greatext throw light. The OP does throw much better than My Fenix P3D, but it is not a MRV, or D-mini with the smooth reflector. It does have very decent throw...out to 80 or so yards.
2. You can either have very good brightness or long runtime, but not really both. Like x2x3x2's review shows, The light is pretty bright with RCR123a's, but it does not run for long on them. The 18650 will give you great runtimes, but dimming and not as bright. You do get a nice low mode with the 18650 that you do not get with 2 RCR123's, where low is about as bright as high. CR123a's give you good brightness and a decent low mode if you do not need to use rechargeables. Keep in mind that even with the 18650 in it is is still brighter than a SF 6p with the P61 bulb.
3. There is some color shifting between low and high mode. My light is like all those I have seen in the reviews so far. It has a somewhat warm white tint on low, but a cool white with some purple in it on high. That is sad to me, because my first rebel light and the reason I bought this one...my Fenix P3D, keeps its nice warm white tint throughout its power ranges. This light unfortunately does not.
All the above being said, The M1-R is a well made light that provides 2 modes of brightness, very decent throw...very decent (or good) brightness, and will work with three different battery types. I believe as long as you do not expect too much from it, you will be greatly happy with it. I believe it is the Honda Accord of lights. It will always deliver what you reasonably expect it to do. Just do not expect it to be a mini MRV with a perfect white tint like I did when I bought mine.
Edit, as I often do, I expect a light (especially one from LP) to be perfect when I get it. I was disappointed with the M1-R when I got it, and sold it in the b/s/t section. I realized later thinking about it...and no longer having it, that it really was a nice-not too big-not too small light. It would throw well out to 80 yards or so, and it did not give me the "watch the small dancing spot" experience that my beloved SurvivorLED does when walking with it. Its beam kind of reminded me of a led version of my old SF 9AN...which was a very good light.
Because of this...I just ordered another one.