They are almost the same thing.  The only differance between the Ravin and th Steeze (other then cosmetics) is that the ravin uses a more durable base material, and the steeze uses a faster base material.  The black base found in the center of the steeze is a little bit faster, were as the base on the ravin tends to be a little bit stronger.  Bases are like a tetter totter, you have durability on one side of the tettertotter, and speed on the other.
as far as core, mounting plates, and build, the skis are exactly the same.