I can confirm that the new Centurion lounge (moved from Terminal A to C, the new one that SkyTeam uses) does indeed have the inner "Centurion only" room which is extremely nice, although the main lounge is very nice. The furnishings and staff support are different. For food, it's a matter of small cold sandwiches/nuts/ice cream things versus a served dinner menu with appetizer, about three main course choices, and dessert, all from BA catering. Very tasty and appealing. The regular side had California sparkling wine versus French champagne in nicer glasses for Centurions. I was impressed.

BTW, this is on the mezzanine level near gate 14, across the concourse and up the stairs or small elevator from the gates, including DL's gate (IIRC 11). The same elevator and stairs also lead to the AR SkyTeam lounge, which wasn't bad before except for horrible wifi service. The Centurion lounge gives you a small piece of paper with an easy wifi code but it's the same for everyone and allows multiple devices.