Very nice, would like regulation
I really like how much light power is packaged into this small format. It is bright! It sits well on your head as well. The lens swapping capability is also nice because it puts the light right where you need it. I use it a lot for working on the car as well as for other outdoor activity.
The only improvements I can see is to add a current regulator to maintain constant brightness when the battery starts to die out. It would also be nice if the outer shell was made out of heat sink metal (for heat dissipation) so that the boost mode can be sustained longer.