Good read with some crudeness, drinking, and spiritual content.
After Sabrina and Daphne Grimm's parents disappear, they are shuffled from foster home to foster home, until they come to live with a crazy old woman who claims to be their grandmother. Only their grandmother is supposed to be dead.
It turns out Granny Relda lives in Ferryport Landing, a town inhabited by Everafters, characters from fairy tales. Snow White teaches the local women's defense class, the Bad Apples; Prince Charming is the mayor (and divorcee of at least three princesses); Puck, the Trickster King, is always wreaking mischief; and the Big Bag Wolf lives down the hall. The sisters learn that they are the descendants of Wilhelm, one of the famous Brothers Grimm, and that their parents have been kidnapped by a shadowy group of Everafters known as the Scarlet Hand.
Mostly the kids are encouraged to behave in a positive and honest way. This doesn't mean they always do so, but when they don't they often face the repercussions. Prince Charming is thrice divorced. In the third book the Big Bad Wolf contemplates suicide, as he begins to lose control of the Wolf part of his character and fears he will become a danger to the Grimm family. In Book Four, Puck admits to hating his father (at his father's funeral, no less), but after what we've seen of the father, it's certainly explicable, if not exactly a lesson in forgiveness.
Magic can be used for good or evil in these books, and there is not necessarily a different source of power for the two, as there is in Narnia. Even so, the lead character, Sabrina, shows the danger of humans using magic. She has trouble handling items like magic wands, because she becomes addicted to the power. Though others in the book, such as her little sister Daphne, can use such things without incident, Sabrina's issue is a useful starting point for a conversation with a child about the dangers of the occult. True occult symbols are not very present here, however, any more than in traditional fairy tales. Though the witch Baba Yaga is downright creepy, just as she was in old fairy tales.
The girls' social worker has "The Purpose Driven Life" in her office in Book Four. Since the social worker is not a positive character, it reads as a low blow against Christianity, at least to me.
Book Six, which I have just finished as of this writing, dealt with some interesting issues involving demon possession (in the form of the Big Bad Wolf), not that it is explicitly called that. But it would be a very good starting point for a discussion on the subject.
Battles with giants, Jabberwockys, etc. Some hand to hand among humans and other characters. A modicum of gore. The mark of the Scarlet Hand is...well, a Scarlet Hand, a hand-print made with red paint to resemble blood.
Drug and Alcohol Content
The smoking Caterpillar from Alice and Wonderland makes and appearance, and Robin Hood's merry men drink and get drunk. The children do not partake. I may have forgotten one or two other mentions.
A kiss here and there. Sheriff Nottingham does refer to Snow White as a "trollop" (She's not one.)
Crude or Profane Language or Content
Most of Puck's comments are disgusting in some way. He often calls Sabrina "dogface" or worse, and she makes a reference, in Book Two I believe, to him being the sort of person who would throw "his own poop." Ew. Not a character I'd want my kids modeling.
There's no doubt the books are fun, funny, even charming, with their cloth binding and gilt edges reminiscent of turn of the century volumes (The paperbacks aren't half as pretty.). They look terrific on the shelf. But the age at which these should be given to children is somewhat harder to determine.
The first two books suffer mostly from the "Ew, gross!" factor (What do you expect with Puck around?)
In the third book, the age requirement goes up somewhat, as even the author will admit, as the Big Bad Wolf considers killing himself when he begins to lose control of his dangerous transformations.
The comment about the Purpose Driven Life seemed to me to uselessly lower the quality of the series.
These books are a fun read...you might enjoy them, especially if you like fractured fairy tales and can stomach Puck's antics. Fairy tale reference from Oz to Wonderland to Perrault to Grimm abound--even a couple mentions of Narnia! Still, it might be best for parents to read this series before their kids do (or along with their kids), to decide.