I had the privilege to sail on the January 24th cruise around New Zealand together with 6 friends. Overall it was an excellent cruise. However, it helped me immensely to be able to read others' cruise reviews, so I will write one too and point out a few possible pitfalls.
There is little parking at Station Pier for Melbourne embarkation, so I was dropped off. The road leading to Station Pier was clogged and progress towards Station Pier was slow. At Station Pier one of my friends got a wheelchair and our whole group was fast tracked through the embarkation procedure. Otherwise there was a long wait, but that is to be expected with 2.000 passengers.
Two couples had balcony staterooms on Deck 9. The cabins were well appointed but a little small, because space that would otherwise on the inside is used for the little balcony. The balcony is quite small - only enough room for two chairs and a small table. Still, having room service breakfast on the balcony was wonderful.
I had an interior cabin. The twin beds in it made it feel more spacious than the same cabin with a queen bed. The bed was comfy and had lovely smooth sheets and doona covers. The bathroom was well fitted out. Just be aware that there is only one Australian powerpoint so you have to juggle recharging your electronic equipment.