UPDATE: New Flickr Album Here: https://www.flickr.com/photos/garrybunk/albums/72157691589882004
So I received my NiteFighter BT40s yesterday (unexpected fast shipping) and I'm quite impressed. It's definitely a step up from the $15 (+ shipping) Ebay MJ-872 clone. Bought it on sale for $23.XX.
First off, the lights are identical in size; I thought the NiteFighter would be a tad longer, but it's not. They are pretty much identical in construction, except that the silicon button (one "button" works the up & down switches) is much better on the NiteFighter. Like Andy has mentioned previously, the nubs on the inside of the silicone button are in the opposite direction of the switches, but it works fine. The rear of the light unscrews and reveals the driver (which I have not pulled out all the way yet). There is a nice o-ring at these threads. The front bezel unscrews easily (tip - use snap ring pliers to remove these easily), however there is no o-ring here. The bezel does screw tightly up against the optic though which will keep it mostly water resistant.
The optic was a little tough to pry out, but after working around and around I finally got it to pop up. It's not secured by anything other than the pedestals resting in holes, the openings pressed over the LED domes, and the bezel screwed against it. The emitters are mounted on a single pcb which is mounted against a solid backing which is part of the light body!!! Woohoo! (Note - I checked the $15 clone and it is identical too.) There was even a good amount of thermal compound in place evenly spread out! (Note - the $15 clone had way too much of a very runny compound in place.)
My light tested at the following current draws on 2 fully charged unprotected cells in a Pannova case:
Low-0.43A (20%)
Med-0.95A (44%)
High-1.43A (67%)
Turbo-2.14A (100%)
EDIT - I believe the original "2.14A' measurement was a fluke (perhaps higher current draw due to lower input voltage?) Turbo should be 1.75A for 0.875A per emitter before losses.
These currents are higher than I tested on the $15 clone (which reached 1.48A on high. The 2.14A on high roughly translates to 1.07A per LED. An XP-G2 on aluminum star @ 1.0A puts outs roughly 350 lumens (not accounting for losses), so we're talking roughly 1,400 lumens. I do believe this light could be pumped up quite a bit more. (Note: I was experiencing quite a bit of voltage sag even when I tried 4 cells, and I wonder if that is due to the battery pack / lights cabling. It's possible that the light would pull more current with better cabling, high-drain cells, or from a power supply.)
There is driver hum in all modes except high. (The $15 clone also has hum but I could only hear it when held up to my ear.) I don't believe this hum would bother me in actual use. I'm not susceptible to PWM, so I can't comment on noticing any. There is a slight fast fade up and down from one mode to the next.
I compared the tint to a XM-L2 T6 3C and an XM-L T6 4C and I'd say the NiteFighter is between the two, but very close to the 4C, a nice creamy white, definitely not orangish.
My PhotoBucket gallery is here, but here are a few pics posted:
Driver (same Andy?):
Bezel removed revealing star mounted with thermal compound:
Solid backing! Direct thermal transfer to the body!
For comparison, my older $15 clone:
Two side by side (NiteFighter on the right):
Again, NiteFighter on the right;
NiteFighter on the LEFT this time:
Sorry, no beamshots yet. On my basement wall it defintely looks like a wide swath of light as expected (same as my $15 clone, but a bit brighter).
UPDATE 10/2015
new close-up driver pics:
other side:
-Garry