We need to start some 'BLF funds for reviews', not necessarily for this light (because it's so expensive), but in general. I would easily pay 0.5-2 $ to see some reviews of certain lights that haven't been reviewed so far. The reviewer gets a free light, which is randomly bought (read - not selected by vendor). So all sides win. Or is that a bad idea?
The only cheap and safe Chinese reseller that I know of that makes it cost effective to return merchandise within the US is DX. They can usually price match their competition and refund, exchange or credit broken or returned merchandise. If the merchandise is broken, they will pay up to 1/3rd the cost of the item to return it to their US location.
If DX carried this light and the reviews were good, I wouldn't hesitate to buy it. Unfortunately, I seriously doubt it could do well on only 3 x 18650's.
The best way to do a beamshot comparison would be to take a side-by-side photo with manual exposure stopped down until the hotspots do not saturate.
When you use auto-exposure like that, the camera will try to expose such that stuff in the flood area is not too dark, which results in the hotspot saturating the sensor (which have limited dynamic range compared to human eyes) so it's impossible to tell which is brighter.
I have to add to this that i had that Trustfire SST-50 ordered from lightake.com. It measured only about 3000lux in my lightbox. As comparison my Mag85 reads about 5300lux and WF-1300L is around 5000lux
So it won't go near 1300lumen. Also tailcap reading was 1.8 - 2.0A