I would choose 15mm, but largely as a "poor man's" 28mm. I'd love to see Copplestone VEG Barsoom. I even looked at try to repurpose the Barbarica range, but that was ever going to work. I'd like to do games where players could fight between flyers/boarding actions and earth born players could leap between ships (although maybe not to the extent seen in the movie). Alas, none of the 15mm figures out there have met my hopes/expectations for this genre.