Panasonic Emergency Light, in my opinion, is going to be very useful in an emergency. It has the capability to take in any type of batteries (from AAA, AA, C to D size batteries). And it just take one battery to power on the light (yes, even a AAA battery), thanks to LED technology (low power usage).
The beauty about this flashlight (some may not agree) is the simplicity of it. It does not have fanciful circuitry to auto-switch the battery when one is drained. Instead, you have to rotate to a battery of your preference (I believe it is a matter of the battery contact point) to use it.
With this design, I think it will make this product cheaper to produce, and easier to maintain or troubleshoot if there is any problem. This product, according to Panasonic Japanese website, will be available from end-January. No mention of pricing. Here is another picture of the product (BF-BM10) with the light on.