I read that book at the end of August. I was very excited when it was published because it was always my favourite story in the Silmarillion.
It was interesting to read the different versions of the tale, it's history and the Lay of Leithian.
The comments of Christopher Tolkien revealed some very interesting background facts and developments.
All in all a great story and a great book.

Just started to read that book after I watched the show. I'm curious how many differences exist. But it's making me sad already.