Gaiman, to me, is the king of taking an old fairy tale and putting a new spin on it. He's played around with that theme in subtle ways with Sandman, "Snow, Glass, Apples", and "Chivalry", and now he's done it again with The Sleeper and the Spindle. He brings a character who might be Snow White and drops her into another story starring a character who might be Sleeping Beauty. And what he does with it is nothing short of brilliant.
I'm tempted to say more, but experiencing those twists and turns on your own is what makes the story so engaging. If you want, you could find out more about the story if you choose -- it raised a kerfuffle of controversy when it was released, as I recall -- but for me the real joy of reading is discovery, and I'm certainly not going to spoil anything.
I'm not one to pay a lot of attention to artwork in a book, even in graphic novels. If it does what it needs to do to convey its part of the story, it blends into the background of the story. Here, though, the artwork is such a standout that it deserves the time for you to pore over it, examine it. Riddell puts a lot of detail in his work, and while there aren't any hidden items to be found, there is certainly a lot to see and admire.
Neil Gaiman is one of a very short list of authors where it's difficult for me to be objective about his work. I thought this story was fantastic, but I say that about a lot of his stories. Take that with however many grains of salt you need, but if you like a fractured fairy tale or two, this book might be just for you.