First: This light was purchased for my own pleasure, with my own money. I've received no compensation in any way for this review.
I got me a DQG Slim 1/2AA Ti. I also purchased a Ti extension tube with it, so I'll probably mostly be calling it a slim AA, and I can only test it with AA/14500. I will only refer to the light with the extension tube installed, and I doubt I'll ever take it off.
First impressions: Wow, this is small. It is about 1mm longer than my D25C Ti, which takes a 16340. It's much thinner, too. It's also remarkably smaller than my ThorFire TG06S, the only other light I own that accepts a 14500. The DQG's outer diameter is almost as small as the TG06S's battery tube's inner diameter. The threads are a bit gritty, and unlubed, so I'll have to fix that. The fit of the extension tube into the head was a tiny bit off, so it was very tough to tighten down. It was bad enough that I was worried and checked multiple times to make sure I wasn't crossthreading. It just really puts the TG06S to shame, which is actually as long as my ZL SC62.
My ThorFire 750mAh 14500 (yes, I know, I need to grab a Vapcell or that new Shockli) fits fine. I believe it is a protected cell. I haven't tried alkaline or NiMh yet. I will eventually, but probably not soon enough to be relevant for this review. It supposedly works even better with NiMh than Alkaline, so I'm happy with that. I didn't realize that I could have gotten three (instead of one) extension tubes to gain 2xAA capability. I may still, as the tubes are available super separately (and have been put to great use by CRX making flashlights out of just the tubes). This suggests that the boost driver in here is pretty nice. I'd imagine you could even run 3xAA and it would treat it pretty similarly to a single 14500, but that would be a loooong flashlight.
The mode order is L->M->H and it loops as you'd expect. There does appear to be the dreaded next mode memory. I'm not 100% sure, but it seems that the light comes on in whatever mode is after the mode I turned it off on, and pretty consistently. My example came without a pocket clip (oops) but with a tiny keyring on the tail. It can tailstand with the keyring (or, alternately, a lanyard or something) installed. The tail switch is metal and clicks with authority. There's a trit slot in the tail switch button, so now I have to go explore that world (side note: are purple trits at all bright?).
The bezel does unscrew, and there is an interesting optic on the light. Rather than a cylinder over the LED, it looks to be a cone-shape. The beam is beautiful (I opted for neutral white) and without artifacts. There is a tiny strip of GITD tape inside, below the upper edge of the TIR optic. The LED is visible below a shelf, and part of what appears to be a driver/MCPCB combo is visible. Make sure you know what you're doing if you want to swap LEDs on this one. The driver is not visible from the battery tube, only a copper-looking positive battery contact surrounded by a black foam. The tail has a small steel spring, surrounded by a white plastic. I've not disassembled the tail, as someone else had a bit of a misadventure there and I don't have any mods planned currently.
As far as build quality, the light is built incredibly compact. With that, there is a feeling of lightness that could be mistaken for cheapness. There are some bits that actually seem like they might be a bit cheap, in particular in the tailcap. However, I've not disassembled that section, so I can't say for sure.