The only sounds (during Campaign playthroughs) were the occasional curse as a Jackal sniper ended a battle. Otherwise it was eerie silence. It's scary for us because we can't tell what they're thinking. The groups of journalists got on very well, in spite of working for rival publications -and played a ton of co-op, multiplayer and Forge. Campaign scoring seemed very popular and I can say that some of the press are total achievement whores. A small group came back after they were theoretically done, to go through co-op on Legendary because they were missing one scoring item they felt they could unlock.
Expect to see reviews landing on just about every review source you can think of on 9/23. And stop sending me Xbox Live messages about the game, I think the thing I had to sign means they can set everything I own on fire if I talk about it.