I vastly prefer the standard Kyurem over either Black Kyurem or White Kyurem because it actually looks decent that way.
It's a tough call between the two. White Kyurem has better competitive viability, while Black Kyurem's design is less atrocious. I guess I'll vote for Black Kyurem. White Kyurem just looks way too dumb, I don't care how good it is in a battle.
It's kind of disappointing that we got those two over a combination of all three, a return to the original dragon before it split apart.