I had a superb English teacher in high school who spent a couple month focused solely on that time period and the expatriates and their lifestyle, writings etc. Because of this I think I got a lot more out of the movie than others did. There is a lot of small jokes and brilliant insights. I recommend reading up on Hemingway, Gertrude Stein, Picasso, etc. before watching in order to fully appreciate the nuances. I have found that I either enjoy Woody Allen films or passionately hate them. His films are some of the only films I have trouble separating my emotional feelings from the technical/creative aspects of the film itself. ie: I hate the movie Citizen Kane but I can appreciate it's cinematic value. I enjoyed Midnight in Paris, it was an okay film, however the premise of the story is more interesting than the story itself. Regardless, I recommend watching it. I doubt you will be disappointed, as long as you don't have high expectations. Once you watch it, let me know what you think.
I feel like Woody reprised this amazing scene, if only slightly: http://www.youtube.com/watch?v=OpIYz8tfGjY only this time instead of Marshall McLuhan suddenly stepping on camera, Owen Wilson's character gets to use first hand knowledge of a Picasso painting from his experience the evening before. -Not exactly the same but it gives the same sort of satisfaction to the viewer. -Very enjoyable. Two thumbs up.