My husband (age 50) and I (age 44) have previously cruised three times on Holland America and twice on Disney. We've also done a few one-time cruises on a number of other lines. We decided to try Princess because it offered an Australia-New Zealand itinerary with dates that would work for us. We honestly didn't have high expectations for Princess and expected it to be a notch below HAL.
We were very pleasantly surprised. In fact, we thought this was our best cruise ever.
We flew to New Zealand on Air Tahiti Nui, stopping over in Tahiti for a few days on the way. That was a fun break and Air Tahiti Nui's business class was excellent, with comfy seats and unusually tasty food. We returned from Sydney to Los Angeles nonstop on Qantas, which also has a very good business class product. We were able to sleep well on both airlines.