Solar-powered space-pop is how Artists Direct put it. If you like the post-grunge bands of America - Flaming Lips, Beck, Mercery Rev et al with a bit of Doves, Alfie, Athlete thrown in then you'll love Grandaddy.
God I sound like Jo Whiley!
That's fuckin' ingenious, if I understand it correctly. It's a Swiss fuckin' watch.