The problem with EK 777 is that there is always a chance is J that you get a horrible old seat without lie flat, at least hard product on A380 is guaranteed. (I also prefer new 777 as service levels are better in J).
Luckily not many 777 left with the non-flat beds now in J class. Prefer the 380 personally as to go for a wee, you don't have to climb over the adjacent seat if you are not in an aisle seat or have someone try and climb over you if you are!
Not sure what you mean by service levels being better - thought this was mainly a function of the crew and you get good and poor on both types.