Welcome to zombies, Cubano style! This movie was effective on many levels. It's a good comedy, with tips of the hat to other films in the genre, like Braindead or Resident Evil, and with refreshing humour. It is also a zombie film, although the horror is minimal. But more than this, it is a social commentary on Cuban life style, with great quotes like "It doesn't look that different to me", when zombies roam Havana.
Unfortunately, afflicted by international isolation, Cuban culture is not something many people are familiar with, including myself, so I can't say if Cubans are really like depicted in the film. I can tell you that, placed in a small seaside town in Spain, the movie could have had almost the same effect. The heroes are ordinary, stupid and selfish, but they grow on you.
Bottom line: If you like zombie flicks, comedy and/or Spanish film, then you will love Juan de los Muertos. I enjoyed it and recommend it.