As first-time cruisers, we chose a ship and line recommended by friends. The Marina is a new ship with penthouses that seemed to offer plenty of room, so we chose that. Our stateroom was large and very comfortable, with a big verandah and two desk spaces on a counter that stretched the length of the room. It also had a huge walk-in closet and very well designed, large bathroom. Our only regret was that we chose a stateroom at the very front of the ship (10002) and the view from our verandah was partially obstructed by a large white lighting fixture. Also, we were right under the bridge which was a bit intrusive. We had some rough seas and they were more apparent at the front of the ship than in the middle.
Service was excellent in all areas: stewardess, butler, dining room, computer center, reception. The food, as we had heard, was really wonderful, on par with restaurants in San Francisco, near where we live, especially the four specialty restaurants. Although there was nightly entertainment and a casino, we didn't participate, but we heard others compliment them.
Embarkation couldn't have been smoother, and our stateroom was ready soon after we boarded. In the meantime, lunch was served in two of the restaurants. Our bags arrived promptly. Disembarkation was equally efficient in Venice.
We did not take any of the Oceania shore excursions, except the bus ride to Florence from the port of Livorno. We explored the ports on our own.
As first-timers, we found we felt constrained by the schedule of ship life: a certain time of day to be back onboard, for example. There is no time to go into places in-depth. You get a quick look at highlights, if you've done your homework, and then it's back to the ship, with all its glitz and service.
One of the surprises--and this may not apply to the older and smaller Oceania ships--is that the "country club" attire requirement for dinner is interpreted to by some to be pretty dressy, to the point of long dresses for some of the women. Men wear golf shirts or whatever, but women tend to dress up more than I expected. In a way, I felt as though I were being coaxed into a lifestyle I wasn't really comfortable with, between the intense level of service and the affluence of other cruisers. It's a matter of personal preference.
The sommeliers really push bottles of wine at lunch and dinner, and I didn't see one bottle for under $50; you are able to have it at subsequent meals, though. The boutiques onboard are high-end, the wireless charges ridiculously high, but overall, if you like cruising, you'd probably really enjoy this ship. It's beautiful, new, staffed by young, enthusiastic staff from around the world, whom I really enjoyed.
By the way, our cruise missed two ports: Amalfi and Taormina, because those were "tender" ports and the sea was rough. This was a big disappointment. I'd advise people to check on how many "tender" ports there are on a given cruise: we had three and missed two because of bad weather.