I just got one the other day. I got a 1x AA version at the same time. The emitter of the 2AA seems to be the same or similar to the 0.5 W Nuwai and RiverRock lights. It is slightly blueish on hi and a little more blue on low. Compared to my other lights and their known approximate lumens, the 25 lumen claim is about on or only a little low. I'd say 15 lumens min, most likely around 20 lumens, but that is a very inexperienced approximation.
It feels fairly well built, not great, but what I'd expect from a sub $20 light. I paid $15 from Botac. It uses an optic, but looks like a shallow one, so does not have a super tight beam, it has a decent spread out center and good spill. The high level comes on with the first press of the button, then low, then off. A useful setup, and I have been using it around the house the last few days - mostly on low, which is fine for navigation. It is longer than a minimag and even longer than my Inova T3. The tailcap seem seems the cheapest part of the light. The rest of it feels solid, including the button. Smooth finish is hand friendly in normal use, but not so confidance inspiring for wet conditions as the knurling is not where my fingers fall when using the side button. Cheap lanyard on a small split ring pre-installed through a small hole in the tail cap that makes tail standing not so easy. It can tail stand once you remove the ring, but you may need pliers and will scratch the finish. It is a long lanyard ~ 8-10." I'm at work and it's at home.
The 1AA version puts out a lot less light, the claimed 8 lumens may be correct. It is of course a lot more compact and pocket friendly. It uses an actual lens, not the flat glass that is typically called a lens, but a mild focusing lens that puts out a nice even beam. It's single 5mm led put out a decent amount of light in a decent beam with a wide but tapering off hot spot. The beam had about four distinct rings as the light falls off away from center. Claims to last 80 hours on low. That is tempting me to do a run time test.
I like the 1AA better, but because of it's shorter length makes it easier to carry.
Let me know if you would like any more specific info.