One of the problems for me is how late the flight is and the fact that you can't really get a decent meal in the lounge.
I don't like to eat on board when the flight is so late as it really screws up my body clock for returning to the UK.
There is supposed to be a separate section for BA (and QR?) passengers in The Club (just off to the left as you go in) with a slightly better selection of food.

Last time I flew out of ATL I decided to connect to DFW in the early afternoon and then got the BA flight from there, still arriving in LHR before the ATL flight and not having to make plans for a long day in Atlanta having already checked out of the hotel.
The AAdmirals club in ATL was fine and of course then had the FFD in DFW and straight off to sleep on the plane home.
I'll be doing that all the time in the future when I am in Atlanta.

Overall I have sadly had hilariously bad experiences with Centurion lounges in the US (DFW, MIA) but perhaps ATL will buck the trend...!