Here is a sampling of what they had to say:
Chris Jones of Variety: "This show has sufficient laughs and enough genuinely inspired theatricaltheatrical silliness to ensure boffoboffo Broadway returns and, no doubt, a long Vegas retirement. Given the power of the Python brand, it could well be as lucrative as The Producers, a show whose playbook has been very, very closely studied here -- right down to the Chicago tryout, and the gags about gays and the Jews who run Broadway. In essence, Spamalot currently is a very funny, very clever, very pumped up, occasionally messy $11 million version of Forbidden Broadway with a medieval-Python theme. No less. No more. So if they want Gotham critical praise to go with their box office receipts, director Mike NicholsMike Nichols and writer Eric Idle had better start thinking about prodding their generally coasting leads with one of their silly medieval pikes. They might also add some post-facto bite to all the daffy production numbers with their endlessly circling cycle of self-referential gags."
Michael Phillips of The Chicago Tribune: "Spamalot hits and misses for much of its first act but ultimately makes it home on sheer comic goodwill. It's nice to be in the hands of comic professionals, and Spamalot has a few. I liked it, even when it seemed to be the work of a bunch of highly talented Python fans re-enacting scenes from a cherished film and making up some highly variable songs to go with it… Nichols directs this piece with a smooth and practiced hand, not too highbrow, not too lowbrow. It's not amazing musical comedy direction or anything, but then, Spamalot isn't an amazing musical comedy. It's more like the biggest, splashiest Oxford or Cambridge revue ever, with a nod to Vegas at least two numbers are set there, for no reason, a little bit of Olde Muddy England, and a lot of Forbidden Broadway Lite in its Phantom spoofs and Les Misérables walk-ons."
Hedy Weiss of The Chicago Sun-Times: "Eric Idle… is responsible for the very funny 'ripped-off' book and delicious lyrics. He also has collaborated with John Du Prez on the show's elaborate pastiche score, which easily competes with Mel Brooks' creation for The Producers… For the speed and sureness and high gloss and masterful deployment of the impeccably cast actors, credit must go to director Mike Nichols. But he clearly couldn't have done it without Casey Nicholaw, who is making a sensational debut as a Broadway choreographer… Tim Curry plays King Arthur with a hangdog melancholy, a doltish, low-key arrogance and a gleam in his eye that tells you he is up to perfect mischief. Hank Azaria deserves the pay of four actors for his protean shifts from the gay Sir Lancelot to the loathsome French Taunter to the Knight of Ni and Tim the Enchanter. And David Hyde Pierce brings his choir boy absurdity to every soft-shoe number and Gregorian chant. But for sheer star power, there is Sara Ramirez, with her voluptuous figure and a gargantuan voice that moves from opera to jazz to Dietrich and Cher with stunning ease; this is a diva's turn, and she makes the most of it."
Jack Helbig of The Daily Herald: "The best of the new songs are send-ups of such Broadways institutions as Stephen Sondheim, Andrew Lloyd Webber, "West Side Story," and Liza Minnelli. There is even a killing parody of pompous Phantom--and Les Miserables--style ballads, called 'The Song that Goes Like This.' This brilliant song was made all the funnier by the stylings of an as yet unknown singer-comedienne, Sara Ramirez. As the old time entertainment columnists used to say, remember that name. She won't be unknown for long. This Ramirez kid has the stuff to go all the way. As for the show, well, for weeks my sources have been telling me Spamalot is, well, full of a lot of spam. My sources were wrong. This show doesn't shine like The Producers did in its pre-Broadway tryout, but it is very, very silly and entertaining, and it leaves you wanting more. It will be a travesty if this show isn't a hit when it moves to New York."