I have a slightly different take on this. EK infrequently (and on some routes frequently) switches its 777 aircraft on routes that they advertise/ sell as "Suites" with Skycruisers. If you take the long haul from BNE there is a chance that there may not be suites at all and you'll be stuck with Skycruisers that are just a tad better than the J seats. I was reviewing the DXB-BNE flight for the skycruisers for the last few months and apparently all the flights have been with suites. But that is not to say that they can't - if they do, it'll spoil your entire experience and there won't be much that you can do about that.

With the A380 route, you are always sure to get an F product with suites. Besides, the shower is definitely a unique experience. I'd go with the A380 unless you think you'll have several more opportunities at the A380 F product in the near future.