I saw this on DVD yesterday, and really enjoyed it. I don't know what the critic's problems with it were (though it doesn't help there were only 21 reviews on Tomatoes), but it was not unfunny, it was hilarious.
Amy Adams is nice and charming throughout, and Matthew Goode's sarcasm was pure gold.
I honestly think it poor-reviewed, simply because it was a straight-laced romantic comedy. I'd sure love to know from critics what it supposedly needed to do "differently".
More harm has been done by people panicked over societal decline than societal decline ever did.