I think I prefer the white one, has a more "epic" look to it, like it comes from the heavens or something, and the black one looks like he just came out of the ground.
Either Serebii's description of them is wrong, or the reverse legendaries are supposedly going to be on the covers. (The black one on White, the white one on Black.)
Odd looking legendaries, although they feel kinda like cousins of Dialga/Palkia to me.
I reckon if the black one was smart, he'd easily win, because he could just pick a fight in mid-air, and since whitey's arms are also his wings, he can't fly and attack at the same time.
Serebii has a bunch of new info about seven new pokemon, although the one that stands out for me is the fire gorilla, which looks great. But the electric zebra sounds interesting as well.