It is darker than Once Upon a Time, and the German cultural references are like icing to fans of folklore. The shows is fun without dumbing down too much, and an excellent introduction to the difference between folklore and fairy tales.
I'm hoping that the next season of True Blood will help to dissuade audiences that fairy tales are friendly things...
And I must admit the exploration of true monsters and complex relationships to "monsters" is an element in modern fantasy shows that I am greatly enjoying.
A police officer finds out that his family is from a long line of "Grimms," a sort of human that polices the monster world (called vessen) and his adventures when his heretige and day job overlap. You get the impression that Grimms of history were more executioners than policemen, but our main guy's forrays into the vessen world are influenced by his tenure as a detective, and so he is doing his best to use the mundane justice system and avoid Buffy-style slaying when he can. The result is that he is actually building some trust with the well-intended vessen. Meanwhile, the real enemy hangs out in the background.