Sailed from Auckland back to S'hampton on the Oriana world cruise 2007. Briefly, I thought the food in the conservatory was awful, so much so that towards the end of our time on board I couldn't eat it. If one went up later in the evening, around 8 pm, the tablecloths were often stained from previous diners. We started off by using the conservatory mainly because I didn't want to eat dinner in the dining room, due my unwillingness to dress in a tuxedo, but in the end I was more less forced to. The food in the dining room was much better. Most people gain weight. My wife and I actually lost about 7 lbs each.
Another complaint - In the far east the ship berthed in a succession of contained ports which were usually miles from the places listed as ports of call. Passengers were then usually ferried by bus into the relative town/city. This was very often an unsatisfactory arrangement and much time ashore was lost. You can't beat berthing in a passenger terminal and these were often available, but not used it seems. The Amsterdam, which accompanied us a lot of the way, nearly always seemed to get the prime berth (I think Dubai was an exception). A round the world voyage is a bit of a marathon I think and we were certainly glad to get off after 8 weeks.
Lucky you, sounds fab, have a great time!
I Know people that have done this cruise this year ( on the Oriana) and they really enjoyed it. They were tired at the end of it not to mention having gained pounds but they had a great time. Research your countries carefully as to where you want to go.