I have the 4AA version of the Hi Gain. Seems to be a sturdy light. Utilitarian. Seals should make it waterproof, or at least very weatherproof. Belt clip on rear seems sturdy enough. Beam is a bit ringy, but fairly broad and usable. Domed fresnel lens not good for WriteRight. Very solid bipin lamp & holder arrangement. Partially recessed rubber clickie switch on rear is a little stiff. Seems a bit dim on NiMH's, but probably best on alkalines or lithiums and used during power outages, etc. Unique and interesting form factor compared to most other lights. I keep mine around for general use and backup. Can't have too many lights, Right?
I believe LEDCorp sold it as an LED (3AA?). I'd like to see what a 1W side-emitter could do in there, though it wouldn't provide much in the way of heat sinking. Under-driven would probably be plenty bright and have excellent run time. The lens/reflector looks like it's all fused together, so I didn't want to risk destroying it to try and separate them. Front half of light rotates 1/4-turn or so to lift off and expose batteries and lamp, and is anchored to rear half via 3 sturdy screw heads mating with keyholes.
I've had mine for at least 3 or 4 years I think, and it seems fairly durable.
John