Here's a sampling of what they had to say:
Rob Kendt in his Broadway.com Review: "What this sweeping, impassioned Courage does better than any Brecht revival I've ever seen is to give the author's vision, and his vaunted epic-theater style, its full due, without either mummifying it in purported Brechtian orthodoxy or saucing it up with extra-contemporary seasoning…. Streep's performance is worthy of its own lengthy treatise. Suffice to say here that she climbs the heights of this complicated, paradoxical role with restless urgency and intelligence, bringing her bottomless reservoir of physical, vocal and emotional shades to bear. It's a virtuoso turn of the best kind—entirely in service to the play's vision and in tune with its rough music. And this is not the Meryl Show; her costars shine in their own right."
Ben Brantley of The New York Times: "This production in search of a tone, which runs through Sept. 3, is not great, to put it kindly. Nor is Ms. Streep's performance, dazzling though it is, on a par with her best work…. Mixing ingredients from the music hall, the lecture hall, the beer hall and the melodrama, Brecht's epic theater is by design disjunctive…. But there has to be an equal consistency of style among the cast members who here include no less a star than Kevin Kline in a supporting role—the feeling that they are all working toward the same end, O comrades of the arts, as they step in and out of the action, shifting among dialogue, monologue, songs and authorial annotation. Such solidarity of spirit isn't much in evidence…. Desperation, cynicism, passion that should have died long ago but still flickers against the odds: all this is implied in every gesture, every note. For one luminous moment, you understand what this play is meant to be. By the way, with every song she sings, Ms. Streep suggests that, in addition to endorsing vitamins, she could become a queen of the Broadway musical, should she ever choose."
Joe Dziemianowicz of The New York Daily News: "Streep's performance as the iconic "battlefield hyena" as Mother Courage is called is gutsy, but a bit of a letdown. Brecht's lack of subtlety runs counter to her strengths. Instead of the deeply nuanced portraits Streep is famous for, and that we've come to empathize with, there is lots of long-winded talk and surface tics…. Mother Courage is by design episodic and repetitive, so it's a challenge to make it energizing, not exhausting. This one teeters more to the latter due to a meandering adaptation and long, insistent songs, which make for an epic-length three-hour evening. … Streep, who gives 100%, manages to dazzle only occasionally."
David Rooney of Variety: "Is Streep a perfect fit for the part? On the surface, no. She's too refined and delicate to be a natural for coarsened survivor Anna Fierling, nicknamed Courage after she drove her merchandise cart through the cannon fire at Riga. But from the moment she comes into view, yelling "Retail!" as she hawks her wagonload of wares in song, Streep's Mother Courage is riveting. This is a full-bodied, swaggering characterization, emboldened by fierce intelligence, quicksilver emotional shifts, inexhaustible physicality and, most of all, sly humor. Despite modern language peppered with profanity and occasional visual anachronisms, the production sticks to the original 17th century setting during Europe's Thirty Years War. But whether it's intentional, George C. Wolfe's direction and Riccardo Hernandez's splintery wooden design echo the gritty frontier world of Deadwood. And Streep's Courage could almost be that show's Calamity Jane with the addition of shrewdness to back up her ballsy nature and carefully hidden compassion."
Linda Winer of Newsday: "Streep, a theater phenomenon before the movies stole her, is never less than smart and enormously watchable as Courage… But this return to the stage is not quite the expected grand finale to her dazzling summer that included her boss-from-hell triumph in The Devil Wears Prada. Streep, suddenly in a mid-career glam era, works too hard to find a sympathetic psychological naturalism in a character defined by actress Helene Weigel, Brecht's wife…. On a more superficial level, what a pleasure to find this cross-generational barrel of talents for the Public's 50-year anniversary. Kline seems awfully hunky and well-spoken as the army's cook, the mother's sometimes lover. But he offers the evening's most stylish and harrowing moment, delivering 'Solomon's Song' with a grotesque inspiration of a vaudevillian animatronic."