There's probably no way that this movie is going to convince anyone who's deeply religious that their own beliefs are ridiculous. Other people's, yes, but not their own. Maher admits as much near the end, when he overtly pitches anti-religious people to get off their butts and start making waves, and moderately religious people to take a closer look at their "evidence" and their mirrors.
His final admonition, accompanied by images of nuclear explosions, is "Grow up or die.".
Interestingly, he doesn't describe himself as an atheist, only as a doubter, but I think he probably conforms to the definition of "one without belief in any gods". Does he know there aren't any? He forthrightly admits he doesn't. That just makes him an agnostic, one who is not positive about his opinions. But he's still an atheist.
Would I recommend the film? Sure, if you're an atheist. It absolutely reinforces everything you believed about how religion is nuts for sure and often dangerous. It'll also give you some sense of Maher's sympathy for the people he encounters. They all seem pretty nice, sincere, and harmless, except for the one ardent non-Zionist rabbi who's just nuts and whom Maher eventually walked out on. He laffs his way thru most of the movie, and good cheer goes a long way toward making something palatable. But in the 2 bookend scenes at Megiddo, he's dead serious.
I'd like it if everybody would see this movie, but it would make way too many people uncomfortable.
I hope it does at least as well as Ben Stein's Expelled, but, since it's not aimed at an audience of mindless sheep who'll pay anything for a little more reassurance, it probably won't.
Sadly, it didn't contain a single word about separation of church and state.