Nice review. I thought I'd post a few of my own observations.
I ordered one of each metal, just received my stainless model and have been playing with it. First impressions are positive. I'll compare it to my Maratac AAA light since I EDC that one and am considering putting this on my keychain to replace the DQG Fairy brass 10180 light that I also EDC. I also EDC an Oveready Peak Eiger 10250 but it's more similar to the Fairy since they're both mules and more spill than throw.
Beam profile is almost identical to my Maratac Rev. 3 AAA lights (copper & stainless), which is interesting as the CooYoo has a TIR and the Maratac has a smooth reflector. It has decent throw for such a small light. It's definitely more a thrower than floody type of light. I'm shining it right now on the far wall of our basement which is 40 feet away and it lights up the whole wall no problem. They're also very close in terms of brightness on high mode. The difference is the Maratac has a cool white beam with a noticeable greenish tinge; the CooYoo is more neutral white and definitely not warm.
There are two modes, a lower and a high mode; the interesting thing is that twisting it to high you feel a noticeable detente which I assume is deliberate. Threads feel slightly gritty but not bad, somewhat better I'd say than my typical titanium light. I'll try putting some Krytox on the O ring and threads.
Overall I like it. As I'm more of a throw than spill type of guy I'm going to replace the Fairy although this light is about twice as long and a lot heavier. It's still a very small light though so that's not a problem. If they did a QTC version it would be awesome.
I just tried plugging in the micro USB port. It's snug and not loose like some. I'd say we have a little winner here that offers good value for the price.
I'd be interested in other's impressions as they receive their lights.
