"To whet your auditory appetite, we've put together an exclusive preview track featuring just a small sample of new melodies you'll hear as you adventure through this haunting environment."

I really enjoyed the Diablo III score and appreciate the direction they took with this music for Reaper of Souls. The music shown in the clip above seems to have an airy choral quality to it. The songs are also layered such that the individual instruments really stand out in a way I didn't hear in the Diablo III score.

Blizzard also did a Q&A with the Diablo III music director Derek Duke. I cut a snippet from the interview for your viewing pleasure.

""Q. The world of Sanctuary is so diverse. When creating tracks for specific areas, how do you make sure you're creating a unique identity while also providing a cohesive sound across the game?

Derek: It's certainly a challenge, and hopefully one we've done well in Reaper of Souls.

One of the ways we've tried to bring musical cohesion into the Diablo franchise this time around was to filter all the music through a single person and process. The Diablo series was originally scored by a single composer and, while the other Blizzard franchises have benefited so much from having all of Blizzard's unique musical personalities contribute to a project, it really felt like Diablo—and Reaper of Souls in particular—wanted a single voice.

While writing a majority of the music myself, I was also able to leverage themes written by Russell Brower, Jason Hayes, Joseph Lawrence, and Glenn Stafford. Those themes were then built upon, arranged, stretched, and orchestrated to sound as though originating from a singular musical voice.

In addition, all our music was recorded with the same orchestra in the same decommissioned church with the same team over two years.
"

You can read the entire interview on the Diablo III blog:

http://us.battle.net//d3/en/blog/13154927