Viking used to have pricing much closer to O than now. It has steeply gone up post Covid to the point that I can, and did, sail on SB for a lot less this year. They have pretty much lost a loyal customer in us.
Our sweet spot is 11-14 day itineraries, with 14 now being our favorite due to animals at home. It is difficult to find a straight 14 day itinerary on Oceania, and even SB that are not B2B. Viking does offer several, and I wish others would as well.