I was surprised by how good this book was! It's a little like "A Game of Thrones" with it's intricate court schemes, but with a lot more magic. I particularly like the pattern magic, but I hope the elemental side will be developed in the next book.
The characters were solid and well developed. There were a few plot points that didn't seem quite right, but considering this is Williams' debut novel it's not so surprising and I expect his/her writing will mature.
Although this is the first in the trilogy, the story is self-contained, so even if the book isn't quite your cup of tea you won't be left hanging! Hopefully there will be a greater story arc spanning the entire trilogy, which I believe is not beyond Williams' capabilities.