Here is a sampling of what they had to say:
Rob Kendt in his Broadway.com Review: "Roberts gives careful, stilted line readings and moves with a studied diffidence that doesn't seem to belong to the same lithe physical comedienne who caromed so winningly through Erin Brockovich or My Best Friend's Wedding. She's on slightly surer footing when she's still, in tete-a-tetes that play like virtual close-ups, though even from Row D these moments resonate faintly at best… The appropriately rainy climax of this fraught triangle comes off with unexpected force. Ultimately, though, the weather report on this uneven Three Days of Rain is lightly cloudy, zero chance of thunder."
Ben Brantley of The New York Times: "The only emotion that this production generates arises not from any interaction onstage, but from the relationship between Ms. Roberts and her fans… The language must flow like music: sometimes like nervous jazz, sometimes like Puccini-esque rhapsody. Sad to say, this production never lifts its voice in song... [Rudd] comes closest to making music, but in a dispassionate, generic, drama-school-trained way… [Cooper] is alternately perky and indignant in the manner of a sitcom actor doing testy and aggrieved. And Ms. Roberts often gives the impression that she is parsing her lines, leaving lots of dead air between fragments. And yet, and yet. I found myself fascinated by the way her facial structure ah, those cheekbones! seems to change according to how the light hits her."
Howard Kissel of The New York Daily News: "It's not about experiencing a play—it's about telling your friends you saw Her. It's a shame because Three Days, which is about how we misperceive our parents' lives, may be Greenberg's most thoughtful play. When it was first performed here, in 1997, with Patricia Clarkson, John Slattery and Bradley Whitford, it was quite moving. Here it falls flat…. Part of the problem is Joe Mantello's direction. He never seems to know what to do with Roberts. For much of the first act she simply stands, arms folded, in an admittedly fetching black raincoat… Cooper and Rudd give their characters charm, but they often seem to be pushing, perhaps because Roberts projects so little."
David Rooney of Variety: "What Roberts brings is irrefutable evidence of what makes her a star. Even in some unflattering costumes, onstage as much as onscreen, you can't take your eyes off her—the infectious warmth, the radiant grin that erupts out of seriousness and goes on forever, the vulnerability, the disarming physical mix of awkwardness and poise. Those qualities are what most ticket buyers for the sellout 12-week engagement are paying to see. But even the most blinding charisma can't quite substitute for texture. Ultimately, Roberts is unable to flesh out the indistinct contours of an unsatisfyingly written role. Greenberg's play is an odd duck—intimate yet emotionally distant and without a resonating payoff."
Michael Kuchwara of The Associated Press: "The star power that is Julia Roberts doesn't shine as bright on Broadway as it does on the big screen… Roberts, who co-stars with Paul Rudd and Bradley Cooper, gives a small, modest performance that throws off the delicate equilibrium of Greenberg's thoughtful, carefully calibrated play, a two-generational love triangle. The personality—appealing, vulnerable and sometimes quirky—that often defines Roberts in film is missing here."
Elysa Gardner of USA Today: "Roberts does hold her own with two guys who have more stage experience: the young stage and screen veteran Paul Rudd and the theatrically trained rising film actor Bradley Cooper. It's a credit to all three stars and director Joe Mantello that this Rain is a study in graceful, generous ensemble acting… In the end, Roberts makes both women credible, compelling and sweetly funny. And she manages a tender chemistry with each of her co-stars; Lina's scenes with Rudd's heartbreakingly awkward Ned are especially endearing."
Linda Winer of Newsday: "Julia Roberts gives a lean, intelligent, altogether honorable performance in Three Days of Rain, the lean, intelligent, entirely engrossing drama that opened Wednesday night at the Jacobs Theatre… Roberts has the gift of being able to seem grave and bright at the same time. Even at her most uncomfortable—when she doesn't quite know what to do with her hands—she has a stillness, an alertness that suggests that someone is in there listening. With Paul Rudd as Walker, the listening is very good indeed… Ultimately, admirably, the real news is not a certain movie star. The play, which once eloquently announced Greenberg as a major mature voice in the theater, does so again."