Quality always trumps quantity, but management can make or break situations. If you're yourself exceptional but have control over a primitive civilization, you're doing okay. But if you're not a stellar performer who manages to control an advanced civilization, you've really pulled something off. All these questions about population always skirt around eugenics, but there's a good case to be made for encouraging population growth of a people that's respectful towards others and tries to minimize social conflicts. Such people are found everywhere in the world, "race" notwithstanding.