In a world where brighter, brighter, brighter seems to be all most can think about, they have designed lights with efficiency in mind. If you needed a big bright light and a small light for a hurricane kit, IMO it would be hard to find a better candidate for the big light than one of the Lumarays. (I'm partial to the new FL-6)
While 5mm arrays may seem retro to many, what Lumaray has done seems pretty high tech to me. The 600 hour runtime on the new FL-6-2006 is anything but retro.