Here is a sampling of what they had to say:
Eric Grode in his Broadway.com Review: "Primo has turned one of the 20th century's towering memoirs into a lesson in achieving theatrical greatness through simplicity. Sher is lucky to have the words of Levi, whose empathic voice makes him an accessible, even ingratiating guide to hell. And we are lucky to have them both…. Sher offers a haunting, deeply human, unforgettable glimpse at the man who willed himself to survive--for a time."
Ben Brantley of The New York Times: "The great accomplishment of Sir Antony… and his director, Richard Wilson, is that they have translated this act of remembering into an expressly theatrical language that never sensationalizes, never lectures and never begs for pity… Of course no 90 minutes of theater, no matter how fine, can approach the achievement of This Is a Man, in which an entire subculture of suffering is mapped out, right down to its sui generis systems of language and economics. But that is not to diminish the true grandeur of what Sir Antony accomplishes here. Grandeur may seem a strange word to describe the modesty, selflessness and accumulation of small, exact gestures that are the keynotes of Sir Antony's interpretation. But from the beginning to the end of Primo, grandeur is what fills the stage."
Clive Barnes of The New York Post: "In every way--as a human document, as a theatrical statement, as a piece of indelibly powerful acting--Sir Antony Sher makes Primo an extraordinary experience… Sir Antony--looking like any mid-century European intellectual in a trim goatee, and dressed simply in trousers and an old cardigan, shirt and tie--seems totally spontaneous against a bleak but neutral setting that suggests a prison chamber of dark memory. He doesn't appear to be acting in any customary concept of the term."
David Rooney of Variety: "This spare solo piece kicks the complacency out from under its audience as it holds them in rapt stillness. Lasting the play's entire 90-minute duration, that unbroken attention befits an indispensable piece of theater to which it seems impossible to remain indifferent."
Michael Kuchwara of The Associated Press: "The heart of the drama revolves around the day-to-day routine in the camp, where men are reduced to automatons. It is that dogged determination to survive, presented without any fanfare or sentimentality, that gives Primo its soul. Sher is at his best in describing those intricate, inhumane workings of the camp, where deprivation is the order of the day and inmates must learn to adapt or die. Director Richard Wilson expertly paces Sher's bleak journey."
Linda Winer of Newsday: "Sher, whose 1997 Broadway debut as artist Stanley Spencer emphasized a furious, almost effusively internalized energy, will have none of that showiness in this guide through the unspeakable but well-documented level of hell. Indeed, though stories of the camps now have the familiar churning of myth, Sher's respect for Levi's straightforward and meticulously detailed observations is both admirable and awesome… Oddly, the unsaid in Richard Wilson's production lingers beyond the words. Levi is wearing glasses at the beginning and, behind them, Sher's alert eyes seem never to stop looking around."