All A380s are the same, just the newer ones have more updated IFE. The 77W has a 8-cabin F vs 14 on A380, so can feel more personal, but on the A380 you get the shower and onboard bar as well as a quiter cabin experience, if it's your firs time stick to the A380.
The newest F is only on the 77W, but very few frames have it and they don't fly to IAD.