This was our third cruise on Oceania (including one on the predecessor Ranaissance) and the first on Marina. We did the itinerary from Sydney to Tahiti - 25 days - in March/April 2013. I cannot say enough about the quality of this ship. Luxury is found in every aspect of the ship. Among the most important elements is that the ship is very well sized for the passenger count. The Marina is larger than the previous Oceania ships and takes 1250 passengers. Both the physical size of the ship and the size of the staff is perfectly matched to the passenger count. There is never any difficulty finding a place to sit anywhere, whether in the buffet dining room, poolside, lounges, casino, or even getting on equipment in the fitness center. The cabins are very well sized and the space is very well used. The staff is uniformly excellent. I have never seen such friendly and pleasant people who are so eager to be helpful without being overbearing. The food is the best I have encountered on any other cruise line (and I have been on many others). There are four specialty restaurants (French, Italian, Asian and Beef) and each is fantastic with regard to both the quality of food, quality of presentation, breadth of menu and quality of service. There are no additional charges for these restaurants, although reservations are needed. The main dining room does not come up to the same high standard. Although the service there is excellent, and being seated (open dining) was never a problem, the menus and food quality not not nearly as good as the specialty restaurants. As a result, we had 19 of our 25 diners at the specialty restaurants. We eventually learned that on the nights when we could not get a reservation at a specialty restaurant, the buffet was an excellent alternative. The selection and quality was actually much better than the main dining room. As long as you don't mind the informality of a buffet, it is an excellent choice.
We really enjoyed the more casual dress code of this ship. A jacket is never required at any of the restaurants. There are no "formal nights" which for us is a pleasure.
We really appreciated that there are no extra charges for anything except liquor. Soft drinks, cappuccino, mixers, etc. are all free. We were on the concierge level and the concierge lounge was always well stocked with juice, soft drinks, bottled water, small snacks, coffee/tea/cappuccino. The fridge in out room was also stocked with soft drinks and water. Of course, alcohol is available for purchase, but much to our delight, they do not constantly push it on you as is the case on many other ships. If you are poolside and want a soft drink, it will be brought to you. If you want a drink you will get one easily but you won't be bombarded with constant attempts to sell you liquor. Especially nice that that whenever you leave the ship there is bottled water available as you leave. On so many other ships, they squeeze an extra few bucks out of you by selling water to you as you leave the ship.
Now for the one big negative...the pricing of their shore excursions is outrageously high compared to any other ship I have been on. Also, the quality of the excursions is nothing special. At a couple of our ports we took independently arranged excursions and they were much better and very much cheaper (1/2 to 1/3 the cost). One striking example is that at our disembarkation in Pappete, Tahiti, they ship charged $149/person to transfer to the airport by bus (a 15-20 minute ride). We took a cab which cost us $20 for 4 people.