In reply to Billhook:
Even the big brand equivalents are hit or miss I've found, once you get into stuff like external batteries with wiring, recharging and moving parts. Unless it's for serious use, I'd use it, but expect issues.
A year ago I spoke to a Princeton Tec distributor and he reckoned a significant part of the difference was in the tech used with the heat sink elements (I don't quite get that as I thought LEDs didn't require it, but other bits must...), so the cheap ones that claim lots of lumens do get them, but only for short bouts.
Some crazy looking other lights on that link. May be silly and dodgy, but good to see some creativity going on.