I have a problem. I'm heavily devoted to Harry Potter. Actually, it's not a problem. It's a standard. When I read any book/series with a plot that relies on a child coming into his magical powers, I can't help but hold it up to HP. I can't speak for the rest of the trilogy, but to me, The Snow Spider failed...miserably.
If you follow the Hero's Quest or the Monomyth, you'll find the "wise old man" who guides the hero throughout the journey (i.e. Obi Wan Kenobi, Dumbledore, etc. etc.). So in this book, when the grandmother gives our little magician, Gwyn, five unusual birthday gifts to see if he has inherited the magical powers of their ancestors, I figure, okay here's our wise old [wo]man. The feminist in me smiled.
But she gives Gwyn NO guidance. Instead, she says (I'm paraphrasing) "figure it out yourself, I'm going to go dance and be that relative that you think is drunk at parties, but is really just crazy." When Gwyn makes a (fairly horrible) mistake, she actually gets angry with him for failing and places guilt on his shoulders. There's a difference between withholding information and waiting until the right time to teach someone (a la Dumbledore). I don't know if she smartens up in the remainder of the story, but there was a significant disconnect between me, the reader, and this character I assumed would be the one to voice the specifics about this setting.
About halfway through the book, Gwyn's parents undergo abrupt character changes. While I liked that this added some complexity to the family unit, for a children's book that I was already having issues with (she puts the grrrr in grandmother), I felt like the abrupt changes were throwing the book into disarray and weren't emphasized enough to be used to develop the characters.
But that's just my opinion. The book (which pre-dates HP by about 10 years), has won some awards so it definitely has an audience and is doing something right. But in a world with HP (yay), I think it can be replaced.