I flew MAN - ATL - TPA last year with Delta.
The aircraft was (I think) an MD11 - 3 engined. Trying to remember the seat configuration... 2-4-2? I remember liking it as being just two of us we didn't have to sit beside anyone - if you see what I mean.
No seat back tvs and the entertainment was poor compared to Virgin. I felt there was slightly more leg room than Virgin and the seats were marginally more comfortable. Food was better than Virgin (just!)
Atlanta is a big airport and it takes time to get from one terminal to the other. We were supposed to have a 2.5 hour transfer, but the first flight was a bit late and immigration was slow. We rechecked our baggage and hurried over to the gate with minutes to spare.
However, this was the first time I had experienced slow immigration at Atlanta (previous 5 times we had sailed through with very little queuing).