Complex sentence: Some critics claim that the "indie" companies, working outside the "Sof-Rin" system, create a more interesting product not only because they have greater freedom, but also because they have the better directors and performers.
Split into simpler sentences: Some critics claim that the "indie" companies, working outside the "Sof-Rin" system, create a more interesting product. Not only do they have greater freedom, but they are also able to attract the better directors and performers.