Let me start by saying that we did enjoy our vacation. That said, we have cruised at least once a year for the past 22 years on several different lines. Because of the price point, we were definitely expecting a higher-end cruise experience. Unfortunately, several factors left us wondering why we spent the extra money for Oceania. Our cabin, a category B3, was nice, but no better than a Concierge Class on Celebrity. It had a bathtub and a separate shower, but the shower was so small, it was almost unusable (and I'm a small woman). The rest of the cabin and balcony were nothing special and actually creaked a bit during rougher seas. Cabin service was excellent.
We have sailed on ships with 100 to 3000 passengers and the Marina, with 1200+ was a very nice size ship. We never felt crowded in any space, and they really have some nice spaces to hide away in if you want to be alone.
The food was excellent and the best part of this cruise line - in my opinion. I'm not a "foody" by any means, but I did enjoy the dinners in the specialty restaurants as well as the Grand Dining Room. The highlight of the cruise was the culinary class where we learned to cook specialties of the various dining rooms. This is definitely something different and not to be missed.
The missing part on our cruise was the service, particularly in the Terrace Cafe, where breakfast and lunch are served. I think they are trying to make it an upscale experience where the passengers are "served", instead of a true buffet line, but it just didn't work. With a casual meal, it seems that people would rather get their own meal items than have people serve them. Particularly when the servers do not really understand (in this case) English. Plus there was no line, per se, but people just butting in to ask for something. It just didn't work, and I would suggest that Oceania reconsider their serving options in the Terrace Cafe. That said, the food was still good.
As mentioned previously, I have cruised a lot. I don't think I am a demanding customer, though do enjoy the experience of being catered to on a cruise - but am very grateful for the service. I will say that I have never experienced so many "no's" on a cruise as I did with Oceania. Its just not what I expected of a cruise line offering "luxury" cruising. I will stick with Celebrity or SeaDream or try someone else from now on.