Technologically, I'd say Jargon, Elyra and then Biesel.
Militarily, Sol, Jargon, Elyra.
Economically, Biesel, Elyra and then Sol.
I don't think it's fair to say the CoC has a strong economy when it's basically Xanu and a bunch of allies with sparse populations. Sol is much more centralized, owns Earth (which is extremely densely populated and iirc home to quite a few megacorps), New Hai Phong and has the ECF as a soft protectorate.
The ECF isn't a superpower in my opinion. They can't do fuck all in the grand scheme of things.