Walton joins a short and prestige list of authors who have written books who have become rare Nebula-Hugo double award-winners. The last person to accomplish this task was the great Connie Willis, who did it last year with Black Out/All-Clear (see my review). Michael Chabon accomplished the same feat two years before that for his book The Yiddish Policemen's Union which I have still not been able to read.
I like the Hugo and Nebula awards because they give me suggestions of new books and authors to read. I have enjoyed getting to know the work of Jack McDevitt this summer, and have almost completely finished reading his Priscilla Hutchins and his Alex Benedict series of books. The latest of the latter, 2011's Firebird was nominated for the Nebula, but (obviously) did not win.
I was hoping that the great Leviathan Wakes (see my review) would be acknowledged by the Hugos or Nebulas this year. It was my favorite read of books published in the last year. George R.R. Martin's A Dance with Dragons (see my review) was probably the biggest seller, and it was also snubbed. Both of these last two books were up for the 2012 Hugo award, which went to Walton's Among Others.