Not that a movie like this requires great acting skills, but the roles played by Rudd, Aniston and Watkins are at least believable. But the credibility stops there. Most of the other characters are over-acted, and poorly-developed.
And one of my biggest pet peeves: scenes from the trailer were NOT in the film. THIS DRIVES ME MAD! It's like a restaurant advertising a lunch special that they don't have in stock.
Bottom line: save your movie, and save your time.