This movie was a great comedy that also kept me guessing to the end. A lot of comedies turn me off lately because they rely too much on adolescent humor that's gross or mainly sexual jokes. This movie got laughs the old fashioned way and felt like a smart Cary Grant / Katherine Hepburn comedy. It also made me think of the types of British comedies you see Simon Pegg in.
There are a lot of reviewers who panned this quite harshly and when I read those reviews I feel like they were watching a different movie. I'd be interested to know how old these reviewers were - perhaps older people will enjoy this more than people in their 20s? (I'm in my mid-40s). Some complained about the acting - I think everyone was spot on. Some complained the plot was predictable - I actually found myself surprised at several turns the plot took and found it quite funny when the audience was clued into new information that the characters hadn't figured out yet.
Rachel mcAdams had great chemistry with Jason Bateman and the supporting cast were each terrific. The characters were well drawn and funny, and the side plots were all engaging and humorous. I was impressed with the writing and acting, and the pace of the movie never made me look at my watch to see how long was left. I definitely recommend it.