Is Gypsy the greatest musical ever? Director Sam Mendes' revival certainly makes that case because, despite huge flaws in the production, his show keeps hitting height after height, leaving you dazzled and deliriously in love with the theater. Bernadette Peters plays Mama Rose, the mother of stripper Gypsy Rose Lee, a role usually tackled with unvarying fierceness. But Peters and Mendes conjure a woman who is sexier, more sympathetic, and only occasionally given to bouts of raving monomania. This softer Mama doesn't suck up all the oxygen, but disperses the play's energies among the other characters, who take on new fascinations. When you add the unbeatable Stephen Sondheim -- Jule Styne score and Arthur Laurents' rich book (which brilliantly builds a psychological bridge between emotional abandonment and showbiz passion) -- well, it hardly matters that Tammy Blanchard fails to make a completely convincing transition from shy Louise to brazen Gypsy or that, by Act 2, Peters' probing portrayal grows somewhat murky and threatens to destabilize the show's perfect structure.