Interesting how one of the testimonials claims to be giving them out to all of her friends...even though the product is still in the prototype stage. At $8 a piece or so for AA I'm sure it won't be long before four other companies copy the design and sell it for half the cost.
I wonder if they are using standard cells and just topping them with a buck regulator to bring it down to 1.5 volts. Personally I would prefer to have the ability to charge several of them at once in a slot type charger rather than having a cable running to each cell.