SPOILER FREE
What has been levelled at this film, in the press, is the fact that there's product placement and the fact that the character, once choosing to engage with life, undergoes crazy, dangerous and reckless feats with seemingly little or no psychological repercussion.
Some of that is true and I at least see where it's coming from, although I would argue that the product placement in the movie is the ok kind, the real kind. For example there IS a website called EHarmony on which single people date and people do eat Papa John's pizzas (presumably) and if you're setting a film in the world in which we currently live it's not unreasonable to expect characters might interact with products, restaurants or websites much like we do every day. I'd rather that than changing names to DaddyJoe's Pizza or ECompatibility or something. The bad kind of product placement is when characters casually drop names of products into conversations like 'It's an Omega actually' with it having no bearing on the plot, like an advert on the TV (James Bond Casino Royale).

The other point that Walter Mitty is surprisingly brave, all of a sudden, for a middle aged schlub, once the plot demands it of him, is slightly true but, to be honest, it is done in such a charming way, to the strains of Kristen Wiig giving a kick ass, inspirational rendition of David Bowie's Space Oddity and you are so rooting for him, at the point it happens in the film, that you go along with it. Anything more drawn out or believable would stop the incredible, exuberant and brilliant pacing of this film. Well, it didn't bother me anyway.

You, as an audience member, are meant to be inspired by Mitty's seemingly over-the-top, exciting and probably expensive, real experiences in the same way Mitty is inspired by the fantasy life he has earlier in the movie. Watch it like that and it's better.

All that being said, The Secret Life Of Walter Mitty is the best film Ben Stiller has ever made as a director. Are Tropic Thunder, Zoolander and The Cable Guy much funnier? yes, of course,  Walter Mitty is not strictly just a comedy but in terms of juggling multiple themes and multiple styles, while telling an engaging and fun story and making it look incredible and beautiful? THIS is his best work to date.
Also people worried that it might be too soppy, or too simplistic, too overly sentimental or too silly... it's, thankfully, none of those things. It's a surprising, fun, entertaining, enjoyable comedy drama with wonderful fantasy elements and lots of sweetness and surprise. Kristen Wiig is also an unparalleled delight, proving herself, again to be more than just a fantastic comedienne but an actress to watch and respect.

Turn off your cynical or ironic glands, relax and get carried away watching this enchanting, midlife-crisis-as-a-fairytale movie.

8 out of 10