Just picked up the Powermat for the Evo during my lunch break.
I was excited to get back to my office and plug it in...everything I've heard is that the new battery door incorporates a battery as well...

Turns out I was wrong. So the battery door feels like the same material as the stock EVO battery door, however, instead of a battery coming attached to the door--there is a small power cable that runs along the inside cover, and ends in a microUSB connector---that plugs into the EVO's charging port.

I haven't made up my mind yet for keeping it. It will clearly make any kind of a case difficult...

Pictures Attached.