Then I spent the majority of the afternoon on EARTH. As DR Arnold alluded, it's PLANET EARTH-lite, a reshuffling and reorganization of amazing footage from PLANET EARTH with a new narrator (James Earl Jones) and a different theme: migration trying together the three main characters: polar bears, elephants, and humpback whales (though caribou and cranes are also touched on). Adding in those other animals and different sections of the earth (desert, rain forest, both poles) also gives a spotty continuity to the whole thing.
So, the images are breathtaking (if mostly familiar) and the DTS-HD MA sound is imminently superior to the DD tracks on PLANET EARTH.