Whatever the reason, the comparison should be enough to warn off those who shy away from romance that has been lacquered with formulaic glaze, (For the record, IMDB lists five writers as having had something to do with the screenplay, and, in case it isn't already obvious, it's not derived from a Sparks' novel. It's just Sparks-like.)
The movie begins by telling us that its story was inspired by "true events," which could be taken as a way of saying, "Look, what you're about to see is calculated and maybe a little sappy, but what can we do? It's inspired by a true story? Don't blame us. Blame reality."
McAdams and Channing play a husband and wife whose lives are ripped apart when she suffers amnesia after a terrible auto accident, chillingly depicted near the movie's outset.
The rest of the story centers on the way Tatum's Leo tries to re-establish his relationship with McAdams' Paige. His task is made more difficult by the fact that she remembers everything that happened to her before she became involved with him.
Additional complications are added by the suburban family from which Paige had been estranged. Because she doesn't remember turning her back on her parents (Sam Neill and Jessica Lange), she now feels most comfortable spending time with them and with her sister (Jessica McNamee). Leo's left out in the emotional cold.
Paige even thinks she might still be in love with a former fiancé (Scott Speedman), a lawyer with whom she broke up before dropping out of law school, moving to Chicago, becoming a sculptor and marrying Leo.
McAdams and Tatum fulfill their genre obligations well enough with Tatum going the extra mile by revealing (to the squealing delight of a female-dominated preview audience) his bare butt.
Overall, I'd say that The Vow is one of those movies that has a difficult time touching the heart because you feel as if you've seen it even before the opening credits roll. The Vow is also the kind of romance that's geared to offer maximum reassurance, not only because it's devoted to formula but because it's obsessed with surfaces: No matter how bad things get, everyone always seems pretty well put together.
Put another way: Few people have been propelled through the windshield of a car and emerged looking as good as McAdams.