Tinny & Ryan,
I have a photon and recently tried one of the $3 photon-like lights from AntiGravityGear:
* definitely not the same light
* pretty much identical size/shape
* seemed like similar weight, but not being a gram weenie I didn't bother to weigh them.
* photon it noticably brighter. The $3 light is bright enough to be usable for task lighting but I'd definitely prefer the photon for night walking or scanning the canpsite for something.
* there's a big difference in the switch. Photon's seems MUCH more robust
* on the other hand, you can buy 6 of AntiGravity's for the cost of one photon