My answer to that question is a stern 'no'. I've followed Vaughn's career all the way from 'Swingers', I've always been a big fan, and seeing him drool out the clunky, inconsistent and completely unfunny dialogue was just depressing. Ben Stiller's 'Evan' and Richard Ayoade's 'Jamarcus' are similarly inconsistent, never really giving you a feel that they're playing the same character from one scene to another. The lack of credibility spreads out to peripheral characters, especially the police chief, and seeing the film try to create a narrative from a foundation of characters in which I have no faith is completely pointless.
The attempts at "comedy" misses every possible target at which they're aimed, not once is there an attempt at a more clever sort of humour, it's all below the belt and base. To be more specific--the entire script reads like a first draft. It's a script written so all the major plot points could be put on paper and we'll think about the modifying it for more wit and more consistency later: but then that never happened. For a film that took four years--four years!--to make, I find the 'first draft' feel of the writing a most shocking disappointment. Perhaps the best demonstration of the first draft feel is the tagline "Got Protection"--it's crass, not funny, and really seems like the first thing they thought up, and then never bothered to go back and improve it. To see that tagline on the way in serves as the best introduction for what the next 102 yawn-filled minutes will bring.
It's a terrible feeling to sit through a movie and feel angry for it, but The Watch generated in me a real contempt, I'll remember the experience mostly as 'the moment Ben Stiller's and Vince Vaughn's careers ended'. Yes, they'll still be in movies, but the all comedic credibility both of them had, that quality that allows an audience to both laugh-with and laugh-at and laugh-with again (an indispensable quality for a comedic actor) was lost. They set it alight in the backyard and charged admission to the bonfire.
It's not often you'll go into see a comedy at the cinema and come out feeling depressed, but that was my experience with The Watch. I'm giving it my lowest rating.