How many ships are there for the BSG collection though?
Galactica, Pegasus, Viper, Viper mk2, Raptor, Cyclon Baseship, Raider, TOS Raider, those ugly little other Cylon ships, Colonial One.... then you'd just have other random Fleet ships, which apart from the Ringship, Cloud 9 and maybe the Olympic Carrier I wouldn't be that bothered about. You could do the Blackbird too I guess.
15/20 issues? I'm not complaining just saying can't see it lasting as long as the Trek collection. Which from my wallet and house's point of view isn't a bad thing!
Same goes for the Alien/Predator ship collection too, I can barely get to 10 ships in my head.