I'm a Christian who generally believes in the theology taught in Left Behind. That being said, I think Left Behind is one of the worst films I've seen in some time.
To have a good movie, you need to have a well-written screenplay. Left Behind fell woefully short on this. For one thing, it radically deviates from the book. Sometimes this is done to condense a 400-page novel down to a two-hour film, but in this film I saw changes that made no sense whatsoever.
Another thing, there is zero character development. When characters in the story get saved (I won't say who), the book makes it clear that it's a long, soul-searching process. In the film it's quick and artificial. The book is written decently enough where people like Rayford Steele, Buck Williams and Hattie Durham seem real, but in the movie scenarios are consistently given the quick treatment without anything substantial. In another scene where one character gets angry about being left behind (again, I won't say who), it seems artificial.
I realize as a Christian it's unedifying for me to say I disliked this film, but I can't in a good conscience recommend a film that I feel was horribly done. Perhaps it would've been better to make the first book into 2-3 films. Either way, Christians need to realize that to be taken seriously as filmmakers, we need to start by putting together a film in a quality way. I realize a lot of effort probably went into Left Behind, but that's the way I see it.