I've had my M20-X for a couple of months, and I have no regrets about the purchase, whatsoever. It's a solid, beautiful, obviously very-well-made light with an intuitive and dependable user interface. It came with a very nicely constructed holster, which has two extra "pockets" for spare battery magazines, or even 18650 batteries, themselves (I've got a 18650 in one, and a little Fenix E15, in the other!).
It'd make a great gift for the flashlight enthusiast in your life - and I seem to remember reading (in many threads) that this was considered THE standard in a weapon-mountable light. Can't say I'm too surprised to read that. This thing is SOLID.
The only thing I would change about it would be with the side button (Used for changing modes, or accessing the strobe feature). I might design a button that protrudes a little more out of the light, so it can be more easily reached/found, without having to look at the light (The current one is almost flush with the exterior of the light, itself). It's not really a huge issue for me, but could be a slight inconvenience, for LEO use, if they were using it in more harsh environments (rain/snow) and needing to access the strobe feature in a hurry, especially if they were wearing gloves. Again, this is not really an issue with me; but the product line was designed primarily for military and LEO use, so there's my $.02 worth.
After a while, I found the orientation between the button, and the adjacent belt clip, helped me find the mode button just fine (without having to glance at the light), to activate it with my thumb. If holding it utilizing the cigar grip, the index finger works pretty well.
But really, that's the only change I could think of that might be nice to see, in future design upgrades to this particular model.
This is my first Olight purchase - the first of many to come, no doubt. I'm hooked !