My UF H2 arrived today from HK. It took 19 days... I was getting concerned. Tried a NiMH: nothing. Checked tailcap tightness based on your experience, no help. Tried a LiIon: nothing. Got out the alcohol and a bit of cotton rag and cleaned the contacts... tried again: everything works. Although, the tailcap still needs to be screwed down very firmly to make contact.
The closest thing I can compare the H2 to, beamwise, is my RGB. The floody beam is not quite as wide as that of the Quark RGB NW, but they are both similar in not having much if any hotspot and being pretty uniform. The UF-H2's output is obviously blue in tint and isn't quite as bright on high as the RGB is.
The H2 is now my most floody headlamp. Previously that would have been my Lenser H7. The Lenser, adjusted to flood, has a considerably tighter, brighter, less smooth (more ringy) beam than this new Ultrafire.
This UF-H2 is a convenient size to carry in a pocket, quick and easy to clip to a garment for handsfree lighting. It's great for fast, short tasks. If I want a headlamp for more than five minutes I'll probably opt for the Lenser, since it can attain greater brightness, is easier to adjust for light level, and can be focused to a spot. But the Lenser won't fit in my pocket comfortably, so I will have to go get it and strap it on my head. And most times when I need handsfree light, it's a task that lasts less than a minute, so I'd much rather use the light that requires no fuss... the H2.
One more light I'd like to compare it to: the Fenix MC10 Anglelight. The Fenix's beam is a bright hotspot along with spill that is about as wide as, but not as bright as, the H2's floodbeam. I bought the Angle thinking it would be my quick, convenient light that I'd clip to my clothes for short handsfree tasks. Well, the Angle wiggles around too much. It tends to be difficult for me to get it to point right where I need it. And I just about have to get the hotspot onto the work area, because that hotspot is often bright enough to wash out my vision when I try to rely on the spill. Even the included diffuser doesn't help much with that IMO. And it's hardly as pocketable... the Fenix is way longer and larger than the diminutive UF-H2, even though they both run on the same size cell. Both have a switch on the head, but the H2 switch is easier to activate and has better tactile feel.
I think I'll get quite a bit of use out of my new UF-H2. It's not a be-all, end-all headlamp. But it fills a need.
Here's a photo. From left to right: Lenser H7, Fenix MC10, Eneloop, UF-H2, and Maratac AAA (for size comparison).