RO (outdated due to new windows at RO south exit)
Defense wise: there is no space at west and south exit for marines fire plus restriction of movement by window frame at west and 1/2 tile choke point at south. East side is open but there is a wall blocking direct fire plus no marine go through maintenance anyway.
Meta wise: instant deny marines of equipments, easy access to cryo to deny reinforcement (or gain hosts)
Being called up to hanger, open space, direct fire from 3 sides
https://www.youtube.com/watch?v=BYldL_rYu4g