Thanks ledoman for your review. As I said over at MTBR, I may ditch my exact looking model from KD (though 4.2v with different driver) and get this one instead. I think I will practice the potting method on my old one though. My unit (without coil) has 6.3mm of empty space between the driver and PCB for potting. The thread on modding my light's driver (with pics of light) is here.
siata94, I have this headlamp at FastTech on my wishlist for its 2 cell battery case (buy a battery case and get a free headlamp! :) ).
-Garry