For the Non-Believers (Atheists/Anti-theists, etc): This may not be the movie for the average Atheist, and definitely not for the Anti-theists. I think this film poses the same problem for atheists similar to the problem believers would face if they were asked to watch Religulous, or to read The God Delusion. It's not because one of those books or movies will shut down someone's beliefs, but the simple fact that they will challenge people's beliefs, and not everyone is simply comfortable with that. Everyone isn't comfortable with dealing with extreme oppositions to their own personal views so, while I do encourage people to face their doubts and be seekers of truth, I can understand people just wishing not to be confrontational with their beliefs. This movie will provoke an internal confrontation for atheists.
For the "On the Fencers" (Agnostics): Despite the fact that this film may be pegged as a "Christian movie", it does a good job of presenting both sides of theism and atheism. I think that the references to Richard Dawkins (atheists), Steven Hawking (atheist), John Lennox (Christian apologist)or C. S. Lewis (Christian apologist) were excellent resources for people to really refer to and compare/contrast the different positions. What I think is the biggest takeaway for agnostics is that this movie isn't about proving God's existence or not, it's about what's more plausible to be true.
For the Believers: This film will more than likely be loved and appreciated by believers. (Especially Christians) The arguments presented aren't necessarily the same old rehashed claims that you'd normally hear in a Sunday sermon. This movie does a great job of at least presenting some of the reasons why believers can believe in God outside of just "Because the Bible tells me so". Both scientific and philosophical evidence are presented in a manner that, I believe, believers should really reflect upon in understanding their own beliefs. For Christians, it may bring 1 Peter 3:15 to mind.
Recommendation: This film is worth watching for those who feel compelled to watch it. A theater or viewing on DVD would be just fine. If my commentary doesn't move you to watch it, you probably weren't going to in the first place.