All 777's have fully-flat sleeper seats. Some are so-called "coffin" type seats-- in 1 2-2-2 configuration. The "Atlantic" version (and,
I think this is the future config for all AA 777's? Have we concluded this?) has flagship "suites"-- which are nicer, especially if you are traveling alone.
I just took AA950, GRU-JFK and it had the "Atlantic" config-- even though there's only one FTer who considers GRU-JFK to be a "transatlantic" flight
-- and the suites are definitely nicer than the non-suites. By how much? That's subjective, of course. I enjoyed it very much. BTW, as of last week there still was a flagship-config 777 servicing LAX-MIA. Nice.