This really is a great flashlight for the money. It's every bit as bright as the D-Cell maglight I compared it to. The fit and finish of the parts that make up this flashlight are very good quality considering the price point. Good fine threading on the base and the shroud, a real polished aluminum reflector rather than crome plated plastic is a nice touch.
Several factors lead to the fifth star coming off.
First, and foremost, there is no "on-off" switch per say. There are two setups availible for this light, the temp button or the pressure switch. Neither will allow you to tap-on or tap-off like some of the higher priced units. Having to hold down the pressure switch can lead to some reliability issues in a tense situation, and not having the pressure switch can be cumbersome depending on weapon choice. You can always screw the back in all the way to get it to stay on, but that's not a very tactical nor very fast. (especially on a shotgun)
Second, the mounting hardware included with the light is just a couple of thousands of an inch too big. When you crank down the allen screw that tightens the grip on the light's barrel, it just doesn't get quite tight enough for some heavier applications like shotguns. If you'll be mounting this on an AR platform or something with light recoil, it shouldn't be a factor for you. But if you're getting this specifically for a high recoil weapon like a shotgun, prepare to be shopping for a new mounting bracket soon.
Lastly, attention to detail in final assembly is not what it should be. The lamp is mated to the reflector via very fine threads that can easily be cross-threaded and sure enough, they were cross-threaded right out of the box. This affects beam size, brightness, placement as well as the lights ability to handle recoil.
Be sure to field strip this light down to the bones and put it back together with great care. I added some brake grease to the threads to help with threading and water resistance and once the lamp and the reflector were mated correctly, the beam was perfectly focused and VERY bright.
Overall I absolutely love the light. It's a great deal for the money, I'll probably be buying a second one to carry aside from weapon mounting. There are just a few issues that cost it that last star.