I bought two when they first came out and like them a lot ( I've since lost one). It can put out a huge amount of light for as small as it is but will have short runtime at full - 15 or so minutes at max. The ability to adjust the brightness down will allow some pretty good runtimes and decent brightness.
I believe others have experienced an issue with overdischarging that can damage the battery. I do not let mine discharge too low and always keep it topped off. I have had good luck by doing this. I typically charge it at least every other week even it was not used much.
I carry mine with me all the time. If you do a search you may find information regarding a fix for the overdischarge problem that is in the works.
