Based on one cruise on Oceania and 1 cruise on Viking and more than 100 on Celebrity. IMO, based on my experience and preferences I'd say that Viking is a much better fIt. Speakers were more than excellent and the same cannot be said for Oceania. The entertainment on Oceania was less than Celebrity, but it was better than Celebrity on Viking. Both had better food than Celebrity and they had prime rib that was large and flavorful. There was no cost on either line for speciality restaurants. I observed a few children on Oceania and Viking doesn't allow children under 18. This might cause controversy,, but I found more interesting passengers on both Oceania and Viking. I felt the staff on all three ships was about the same. You can look at what's included in each and I believe that the cost may not be all that different.