I've been waiting for a movie that captures the essence of the vampire genre like "Cuando los Amos Duermen" for a long time. Vampires in popular culture have been transforming, becoming better adjusted to the times, but also in a way deviating from the core of what they are: Beautiful, powerful, terrifying monstrous reflections of the worst human instincts and servants of Evil.
Of course, the main reason why Vampires change is that the definitions of "beauty", "terror", "Monster", etc, have been changing. Even the definition of Evil has been changing with the times as society has been gradually becoming more secular. We've had more than 100 years of Vampire movies, so change is to be expected (and celebrated). In my opinion, in the last few decades it seems like vampires have been "killed" not with a crucifix, or by being exposed to sunlight, but because their own overwhelming popularity had made them a parody of themselves.
Count Chocula was intended as a marketing gimmick in order to sell cereals to kids, not as a template for novels and movies for adults. "Why do they glow?" is the question that one of the protagonists asks herself while reading a famous contemporary vampire novel (that shall not be named). "Cuando los Amos Duermen" vampires are definitely not silly, definitely "do not joke", even when it seems like it. They are murderers, they are supernatural, and some of them most likely cannot even remember what feeling compassion is. Also, some humans are even more monstrous than some of the vampires.
The acting is superb, the setting refreshing (the Catalan countryside), the plot well-rounded and satisfying. The setting and photography merit a separate mention: An old, decadent "Masia" turns out to be the perfect match for a centuries old vampire. While obviously not enjoying a Hollywood-Sized budget, "Cuando los amos Duermen" special effects are precise and effective: They are scarce and tend to catch the viewer by surprise, which just makes them more powerful and don't get in the way of the plot.
I honestly cannot find any major flaws and I thoroughly enjoyed it. Right now only available in Spanish, if you can watch it give it a shot, you will not regret it.