Both have it. We traded Computers to SABER for Rocketry, and FREE researched it first thing they did in the MT.
Like AT says, it is not just about the rubber though, even if that is a required resource for some parts iirc, but SCI is also a perfect beachhead for their air forces.
I counted the tiles and if they plant an airfield on the southern mountain, they would only be able to hit some 2 cites on our mainland. A perfect beachhead for airfoces would be The hideaway or The whalepond...
Why can´t we build an embassy with FREE and do a little city spying?
Yeah, the Hideaway or Whalepond are especially dangerous for us to lose. Is it wise to disband those cities if the enemy approaches? But then we'd have to prevent them from landing workers or a settler.
One more comment is that we can draft twice as many mech infantry as Saber has marines so can totally prevent the loss of any town if they pull transports in our range by simply stuffing towns with more units than they have attackers. Since it takes more than one bomber to kill a unit it is impossible for Saber or Free to take one of our towns and then perform a blitzkrieg so our concern about that should be put to rest for now. Since we always have advanced notice of a landing we can also move our bombers where they are needed before they land at any time. I don't think many changes in our defense plans need to be made.
So....it is us SABER will be targeting then?
PrinceMyshkin's reasoning points to a SABER blitz on FREE. This may be even more likely now that FREE is openly harboring BABE.