I would like to offer my "2 lumens" on this light having tested/played with it and also having owned a k40vn
Very nice quality - similar to k40 obviously but rebranded ace beam instead of sup beam.
Seems to generate less heat than the original k40? This could be because now vinh is using thermal pads and copper heatsinking... I ran the K40L for about 5 minutes on high before cranking it down a few clicks. (K40vn was like 3 minutes IIRC). The heat build up seems to be spread out throughout the body better as well. Ok - maybe it generates the same amount of heat but we could say it seems to be better managed than the first run k40vn.
Level 4 (out of 6) was safe to leave running tailstanding. I never recommend leaving lights unattended though so do this at your own risk.
Definately puts out more lumen than the original k40 - I never officially tested a k40vn's lumen output - but I believe it put out around 1350-1400 lumen otf - XPL de-dome beats this now and the PDT has a nicer tint with no hint of any green. My 1st run k40vn did 390,000 lux - some other cpf and blf members reported as high as 480,000 lux but I am not sure how this was measured and with what equipment etc.
This really is a great "base" vinh light - meaning if you don't own any vinh lights and you want to buy a thrower - you should start with this one. If you want a general purpose light - start with the K40mvn. Flooder - tn36vn.
The only flaw is the tail cap - I really wish acebeam would make thumb cut outs like on the k50 and other lights for easier access to the switch - there is an aftermarket assembly option on the marketplace - which works nicely
(link) I have sent this to vinh - perhaps he can get a batch order and include this as an option on these lights.
I do not see myself buying one personally - but I have the K50vn fiat lux already
I also tested XPG2 - did less lux than the XPL oddly even though the hotspot did look slightly tighter and brighter to my eyes. I retested to confirm this obviously. Maybe because the XPG2 puts out less overall lumen it made the hot spot look more pronounced.