that's a hard question. Neal Shusterman has Everlost, Unwind, and other really good stories. Scott Westerfield has the Uglies series, the Midnighters series, and more.
Their writing styles are very different, so it's hard to compare them. However, Unwind, by Neal Shusterman, is by far the BEST book I have ever read, and I've read a lot of books.
So I think that they both have great amounts of talent.