The only Lovecraft book I've read is The Dream-Quest of Unknown Kadath. I thought it was an interesting world, but I didn't like the writing. I enjoyed The Dream-Quest of Vellitt Boe more. Kij Johnson nails the tone and style and expands the world a little bit.

Most of this book was just a quest story through an interesting world. The last 20 pages or so, though, took it to a new level and that was my favorite part of the story.