With this comment aside, this movie is one of the most underrated pieces of work I have ever experienced. It is smart (but not in an overbearing way), and romantic (but not in a way that is just "corny/mushy), and funny, if you appreciate British humor, combined with Louis C.K.
If a viewer is mature enough to handle the themes and type of dialogue (Not absolutely filthy, but in a place where no one can lie, certain things regarded as taboo or inappropriate just fly), then the ideas behind this film all are quite funny.
Certain basic plot holes might can annoy a person who is incredibly analytical, but if you are able to just go with it what is happening, the movie is wonderful. It was quite literally one of those "I laughed, I cried, and I thought about life" type of films.
If you enjoy Ricky Gervais' work in general, you will absolutely ADORE this film. If you don't really like him, or don't care either way, it is still an enjoyable film, with a great cast who make it worth seeing, especially now when you can probably find it cheaply on Netflix or whatever.