Complex sentence: Alford noted that Marcuse, like many of his critics, regarded the book as his most important work, but observed that it has been criticized both for expressing views too similar to Freud's and for diverging too far from Freud.
Split into simpler sentences: Alford noted that Marcuse, like many of his critics, regarded the book as his most important work. He observed that Marcuse's book had been criticized both for expressing views too similar to Freud's and for diverging too far from Freud.