The Station Builder has been fairly useful for making concrete bunkers and modern/futuristic structures without all the intricate trim and gingerbread detail of older architecture. While I still cast the Fieldstone molds far more often for traditional dungeons and castles, the SB has definitely seen its fair share of use. Besides, it makes great "blanks" for creating custom pieces.

The Skematic Pyramid mold looks interesting, although I haven't gotten more than a set of pre-cast blocks to look over and dry-stack. I don't think I've found a good enough excuse for me to buy the mold, though, since I don't play anything that would use that style of structure. A 40K Tau player might find it extremely useful.

The remaining Sci-fi molds don't seem to lend themselves to building exteriors. Enclosed arenas and corridors are their strong points, and most of the exteriors I've seen using them have looked either like some sort of machinery instead of a building, or else appeared far too "busy" for my liking. Of course, if you want interiors, those are the way to go.