What do you want to do, run cargo, run fuel? Do you want to run in safe areas, or do you think you want to go do combat fleet resupply?
if you want to run fuel...or cargo once the external cargo pods are done in a safe area, the base Starfarer is better as it will hold more fuel/cargo (supposedly). The Gemini means less fuel/external cargo capacity (supposedly), but it will be tougher, be warned though, if you use the missile rack, you won’t be able to mine gas clouds, so it’s running from a source where you fill your ship to where you need to sell/deliver the fuel.
my advice, get the base Starfarer and an upgrade to the Gemini. If you find that you don’t like the base, you can apply the upgrade, or if you have the upgrade, you can melt and buy back the base. Consider getting someone to spawn one or the other for you to try out.
btw, it handles like a drunk pig if you get your thrusters damaged, and there are times that if you are damage, you HAVE to land it manually because the computer can’t do it,