I like it both, but i tend to prefer the witch over the sci fi design, maybe is the asymmetry in that design (the one at the left corner) that make it more interesting, and i can imagine in the pieces that are apparently made of metal a engraving who could look very cool.
I think that light,shiny colors would fit the sci fi design pretty good,also painted letters or numbers like in airplanes or war vehicles.
Great job with the concept designs.
