In a Core Fireteam of Hallow Men do you prefer the Spitfire or Missile Launcher? I would like both but at 4 SWC it's a tight fit.
Worth taking both IMO. 2 SWC for an additional weapon in the team is an investment, but it's hard to see where else I'd want to put it for greater effect.
What Solar said. But if you're somehow squeezed for SWC I'd go with the Missile Launcher. A super jumping ML with full link bonuses is truly disgusting, pogo it from behind full cover on turn 1 to clear firelanes/roofs. If it gets knocked out it's still in easy range of a Clockmaker.
If you're going a full 5 stack (or 4 + Stempler) of Hollowmen, then likely it's worth putting most of your SWC into that fireteam since it's quite likely it will be the central focus of your list. That much firepower and wounds in a Fireteam is gross. Plus the two weapons help you to face different scenarios so why not! :)
The missile launcher gets top priority. It's non-negotiable for a HI link to have a long-ranged weapon to get them out of the DZ. The spitfire is optional... you can pay the SWC, or get the multi-rifle that's 60% as good.