Fellow passengers: On the flight out there were a couple of screaming kids but eventually they fell asleep and otherwise people were fine.
How full: Full to the brim both ways.
Entertainment: We only bought a Seat + Bag fare but surprisingly there were lots of TV series, documentaries and music available free to watch or listen to even if you just get the basic fare, which was great.
The service: The service was great — I never went thirsty and the staff were always pleasant.
Food and drink: We had decided to take some of our own snacks but we were still given the choice of a cookie or chips, a hot drink and frequent cups of water if we wanted.
The toilets: Perfectly clean for both flights.
Luggage: We were allowed one 23kg bag each, which was strictly enforced at Auckland Airport. Air New Zealand now has automated baggage check in at the international terminal, with a luggage belt at each station that weighs every bag and won't let you put it through even if it's only 100g over.
The airport experience: Auckland Airport was pretty standard although the Wi-Fi doesn't work well when you're waiting in the line for customs, which was kind of annoying. As expected Rarotonga's airport is tiny, I think there were about four shops and two cafes. But there was a lovely musician with a ukulele to greet and farewell all the passengers, which was a pleasant surprise.
The bottom line: Both flights were great, the ability to watch TV shows was a nice surprise. Flying into Rarotonga is something I'll never forget either, the island is 32km the whole way around so seeing that from the sky was a treat. Rarotonga is also far more mountainous than I expected, which made for a beautiful landing and takeoff.