My latest 1x21700 review is now up on my flashlightreviews.ca website:
Spoiler alert, but it actually meets its rated max spec in my lightbox (albeit briefly). Here’s a blow-up of the max runtimes, showing you the first couple of minutes:
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Thanks for the review!
Somewhat off topic, but hmm…
The Convoy M21F has the flattest line, and has the highest output after about 1 minute 40 seconds.
It looks like if you don’t care about “maximum output for a short amount of time”, go with the Convoy. 
I EDC a Convoy M21C with an XHP70.3 HI emitter.
I don’t know how bright it is, but it can maintain something close to 100% brightness for a good, long time. 
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True, but it also seems to be the largest light tested… and the thermally sustainable max level depends heavily on the size and mass of the host. Efficient LEDs and drivers play a big role too, but there’s no substitute for sheer mass.
The MS03 is surprisingly small for the amount of light it produces on turbo.
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@ToyKeeper
Good point!
I didn’t look at the size of each flashlight, but of course the mass of the flashlight head is crucial for sustaining output.
Yes, good points all around.
The Convoy M21F is very impressive in its regulation, but it is among the largest lights I’ve tested so far.
That said, I should have noted in the review that the MS03 is surprisingly heavy for its size (and top-heavy, suggesting a good heatsink in the head). I haven’t been weighing the new lights I’m testing, but maybe I should start, since this is a relevant point.
I am much amused by the chart showing the very inexpensive Convoy M21F beating the competition, including MS03, over the first hour of runtime. Sometimes money doesn’t buy more useful light.
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FYI, I’ve just updated the review (and all my tables) with weight measures for all my current lights.
The MS03 weighed in at 120g without battery in my testing (192g with the included cell). This makes the MS03 the third heaviest light in the compilation of 10 lights in the group photo in my review – despite being the second shortest of the group.
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I’ve found 10k+ lumen torches pretty useful for photography purposes, even if they can only sustain that brightness for a few seconds. Especially if they can have the optics removed and function as mules. Ceiling-bounce 10k lumens during a photo, and it’s a great way to illuminate things for the camera while also mostly eliminating shadows.
I haven’t otherwise found much use for lights that powerful though… particularly in focused lights designed to get a lot of throw. The brute-force approach to throw is common, but it tends to light up the foreground so much that it obscures far-away objects… so for distance I’d generally rather have a more moderately-driven light with a very tight beam.
Setting aside what’s practical though, high-lumen lights can be a lot of fun. Like, put a photon grenade in Lightning Mode and play the sounds of a rain storm. Or the small ones make a good “wow factor” when showing people how blinding a small light can be.
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