Well, I'm fortunate enough, or foolish enough,
to own both the Surefire M6, and an UltraStinger. The M6, with it's 250 lumen lamp, puts out roughly double the light the UltraStinger does. And, it is much better at long distances than the Streamlight, too.
That being said, the M6 is really a case of overkill, and it looks to me like the 10x is *vastly* better in design and function.
Due to the cost of those 6 lithium batteries, I've used my M6 very little. But in the few weeks I've had the UltraStinger, I've run it (almost) completely down twice now. I have 2 extra battery packs for it that I made, which cost $17 for both of them. I have 3 spare lamps on hand for the Streamlight, and only one for the M6. So really, in choosing between the M6 and the 10X, I'd pick the UltraStinger in a heartbeat. The 10X has got to be the ultimate in design perfection, but it's really, really expensive. As are the lamps, and extra battery packs.
Even buying the battery packs for the UltraStinger from Streamlight is only $30, a bargain in comparison to Surefire battery packs. I'm not saying the UltraStinger is as good as either the M6 or 10X, it's not, by a very large margin. But, for the money, the UltraStinger delivers more than either light.
If you must choose between the M6 and 10X, it's no contest: the 10X wins on nearly every count. Sixty lumens is a *lot* of light compared to other 'conventional' flashlights of any kind. Three hours is a very long burn time for that amount of light, too. And the fact that it's rechargeable makes it so much of a better value. And you have the ultra high light output for those relatively rare occasions when you need it. (And you won't be thinking about lithium batteries, while you are using it.) But if it were me, and I didn't already have one, I'd count the UltraStinger as one fine Christmas gift. You could even buy a spare lamp or 2, and an extra battery pack, to make it a *really* nice gift.
BTW: I am one of the *extremely* fortunate few who never had any problems with any orders to Botach; I didn't know just how lucky I was until relatively recently. I paid $215 for the M6, and I bought a boatload of the Energizer 123's when they were $2, and more when they were $1.50, so I made out very, very well. Of course, it will be a cold day in hell before I give them any more of my money. I feel like I've used up several years' worth of good luck!
But I will use the UltraStinger way, way more than the M6. Odds are, I won't buy the 10X, simply because I already own the UltraStinger (We'll see how long that prediction lasts....!)
I own 6 SureFire flashlights now, but before I got the UltraStinger, I used one of my 3 standard Stingers by far the most. Funny how the standard Stingers seem so wimpy now.
I carry and regularly use an Undewater Kinetics 2L; I consider it an excellent compromise between size, weight, and cost of operation, for a flashlight I *always* have with me; but that's another story.
