Small one really works for me, strong silhouette.
The big one is a big improvement over earlier work, but like decroded said, the detail muddles the form. Start with a strong silhouette, carve it up in big chunks, then start adding details, etc. The perspective on the pipes in the middle of the ship are nifty btw, makes it feel a lot larger than the small ship, I like that.
You need to flip the bit to the left of the pipes btw, to sustain the weird Link to the Past like perspective illusion (which I've never seen done on a sprite, looks funky, kudos):