This was the smallest ship we had cruised on, our last two cruises had been with Celebrity, which we had enjoyed. The Riveria was a great size, big enough for enough variety but never felt busy. We loved the variety of places to eat, we ate 6 times in the speciality restaurants (twice in Red Ginger and Polo). Our favourite was Red Ginger, not so impressed with Jacques. The dining room was excellent as well.
If you are teetotal or happy to drink alcohol brought on board(no restrictions) then you can spend very little as all soft drinks are included . We did not go on any excursions from Oceania all were easy to do independently would recommend investing in Rick Steve's guide to Mediterranean ports.
We were in a basic veranda cabin and it was an excellent size, lovely having a bath and a decent shower. The bed was the most comfortable I have slept in other than one in a hotel in Costa Rica. Personally I would go in a conceiarage cabin next time as I like breakfast in my cabin (only continental available in the basic verandah cabin) . Service was good but I have always had good service on cruises it was no better or worse than others. We were pleasantly surprised by the entertainment, loved the string quartet and enjoyed most of the shows.
Overall fantastic value ( so long as you do not go on the excursions) with amazing food and beautiful ship . We will be back