The light and battery from my ebay link have switched plugs. You can't use original magicshine battery with ebay battery or other way. Battery plugs are male, and light plug is a female type. Not a big deal if you stick to Ebay version, but I just wanted to let you know...
Also, the one from previous post on DealExtreme website have P7 LED, and the one from my ebay link have xml t6 led, which is considered the best light output and being the most energy efficient. Maybe that's the reason why xml t6 is okay with only 2 cell batteries...

Not my video, but you can see the difference between p7 and xml t6 here:
http://www.youtube.com/watch?v=7bRPviZWvk8
I found this picture online lol