I should point out that I have spent more than 2 months on the Explorer this year, so this feels like home. I have grown use to her routine, the staff, the food etc. So even though Voyager is the same class, run by the same company, there are some operational differences that make the two ships very different. Both ships are configured for the other markets they serve when they aren't sailing out of Sydney, Voyager for the Asian market and Explorer the American.
These little difference include things like the way blackjack is dealt, trivia is sometimes in High Notes (a terrible location for trivia), the morning dance lesson is on the Promenade on Voyager, the sports court on Explorer. The time of events was different, sometimes as little as 15 minutes, but enough to make me take a second look at the Cruise Compass. Speaking of which, I can now skim the Cruise Compass on the Explorer as I know what I am looking for, Voyager's Cruise Compass required a deeper analysis, not only because times were different, but the wording and structure of events was different.
All of these things were just a little discombobulating. In the end I prefer Explorer, is it because it is the better ship? better run? Unlikely, it's probably because of my familiarity, with the crew and the ship.
But even on this cruise I am now on (Explorer) things are a little different as there have been some staff changes which have mixed things up.
Ultimately I think that most people wouldn't notice these differences as much as I have, however I have spoken to some other guests who have sailed on both, and they preferred Explorer too, but could't quite put their finger on why. Maybe it's that bloody cone on the lido deck.