Timothy Burke has an interesting discussion of Cooper vs. Rowling. I find it interesting that so many of the commenters liked The Green Witch best of the The Dark Is Rising series; it's my least favorite. My favorite is The Dark Is Rising, followed by Silver on the Tree. I'm also a little surprised at Burke's suggestion that the reader would tend to identify with the Drews; I always identified with Will. Burke is right, I think, that Rowling's fiction is character fiction, whereas Cooper is not. The main characters in Cooper's series are not Will or Bran or anything like that, but the Light and the Dark. What's fascinating about it is not this or that character but the world (as one of the commenters puts it, her 'milieux'), which is much more tightly thought out than anything Rowling or Pullman give. If we want to put it sloganishly, Rowling's is a better story; Pullman's is a better poetry; and Cooper's is a better fantasy. I don't think character fiction is automatically better than other fiction, so I don't think the character-centered nature of Rowling's work is a good basis for declaring Rowling superior to Cooper. I would actually give the reverse advice Burke does; fantasy writers should focus on puzzle fiction, not character fiction, because it is extremely difficult to write good character fiction. If you do write character fiction, it should usually grow out of the story, not be something you set out to write.
To some extent, though, it's futile to rank these types of works. Fantasy is a remarkably broad genre, and none of the greats are really doing anything like any of the others. Take the great examples of fantasy for children and young adults:
Macdonald's Curdie books
Diana Wynne Jones's Chrestomanci books
Cooper's The Dark is Rising
And then the two most recent candidates:
Rowling's Harry Potter
Pullman's His Dark Materials
Not one of these things is quite like the others; they can only blur from someone who has the literary equivalent of a tin ear. They have bits and pieces in common, aand can be compared in very broad terms, but that's about all. And this is as it should be. They all have their influences, but none is derivative. Cooper's world has a cold and intricate beauty to it, like the patterns of snowflakes on the window or the snow-topped peaks of a mountain range, that is leagues away from the messy, and sometimes sloppy, fun of the worlds of Rowling and Pullman.
But the thing I always liked best about Cooper was the rhyme in the TDIR, which is inimitable:
When the Dark comes rising, six shall turn it back;
Three from the circle, three from the track;
Wood, bronze, iron; water, fire, stone;
Five will return, and one go alone.
Iron for the birthday, bronze carried long;
Wood from the burning, stone out of song;
Fire in the candle-ring, water from the thaw;
Six Signs the circle, and the grail gone before.
Fire on the mountain shall find the harp of gold
Played to wake the Sleepers, oldest of the old;
Power from the green witch, lost beneath the sea;
All shall find the Light at last, silver on the tree.
The upcoming The Dark Is Rising movie looks very iffy, though.