Ron Howard's latest film poses something of a dilemma in itself - should we sit back and await the warm, slightly shame-faced glow of the latest Vince Vaughan vehicle, or brace ourselves for an excoriating chronicle of sexual deceit and romantic disillusionment? The answer, disconcertingly, is both.
The opening scene settles on two couples - tentative long-termers, Beth (Jennifer Connelly) and Ronny (Vaughn), and husband and wife Nick (Kevin James) and Geneva (Winona Ryder) - in a classy restaurant, cod-philosophising on "whether you can ever really truly know someone", like wot proper grown-ups do. Moments later, we're firmly in bromance territory, watching Vaughn and James perform a time-honoured, ritual "comedy" best mates dance routine, while their obliging partners look on adoringly, clapping and giggling like a pair of expertly programmed Stepford wives. "I don't think I'll ever forget that", Beth whispers lovingly in Ronnie's ear when the horror is finally over.
The small mercy here is that the sight of two paunchy would-be entertainers embarrassing themselves on a dance floor is all too unremarkable to be unforgettable, though what it says about the film's lurches in tone is telling. While its subject matter - best friend discovers best friend's wife is cheating on him and vacillates over what to do next - is given serious dramatic weight, it's strung together, as if by way of awkward compensation, with a crass, mixed-bag of comic set pieces and slapstick.
Some (like Ronny's discovery of Geneva's infidelity in a tropical garden, which plays for predictable laughs as a wildlife explorer parody) are less successful than others (the surreally elaborate back-story Ronny contrives to keep Beth in the dark, involving morbidly obese school kids and poisonous vegetation is actually pretty funny). This isn't such a concern while Ronny's predicament is being established, when all is still to play for in terms of narrative and tone.
It does become a problem, though, when he confronts Geneva. Her initial response, surprisingly, allows for the genuine complexities and messy disappointments of married life (to paraphrase: "I would rather not be having an affair, but my husband hasn't slept with me for six months and spends his Thursday nights being seen to in a massage parlour by a young Vietnamese girl, but thanks for asking").
Disappointingly, the film shies away from engaging with any further emotional home truths. Geneva transforms into a cartoonishly unrepentant Jezebel, while Ronny and Beth's own issues (including Ronny's fleetingly sketched former gambling addiction) are put on ice to keep the focus on Ronny and Nick's regressive, sacred man-child bond. There are several films competing against each other here: a pretty cynical, dark-hearted relationship drama, a straight-down-the-line rom-com, and a woeful brom-com, bolstered by a Queen Latifah cameo in which she makes frequent references to her 'lady-wood' to denote rampant enthusiasm, and in which electric cars are referred to as 'gay', accompanied by images of manicured kittens and cute rabbits to enforce the punch line. Suffice it to say, none of them wins.