Having cruised on both Oceana and Aurora this year I would say that they are both are lovely ships. Oceana more modern in as much as younger passengers but that depends on when in the year you cruise. Aurora when I first boarded I got an immediate feeling of traditional style 30s feel, absolutely beautiful ship. Im early 50s so like to think that both vessels suited me. I originally always cruised on Oceana since her launch but when I sailed on Aurora that changed. Hope my input helps. Happy cruising.
Have cruised both Oceana (but not recently) and Aurora (2008 World Cruise). My preference is for Aurora but I think it is very subjective. Aurora is more traditional cruising, formal evenings adhered to, many more cruisers from the 1990's when all cruise lines were more formal. Did see gent turned away from dining room on informal night for not wearing a jacket. I suspect that even in school holidays Oceana would have a younger average age population than Aurora. Aurora has a covered pool for poor weather. In school holidays children have their own deck aft with pool, whirlpool and paddling pool and there are still the other two pools for adults. I also think the children's facilities are bigger and better. It has a separate cinema. I think Aurora has more quiet bar and sitting areas. It does not have freedom dining.
Personally I think it would depend on your age group. I cruised with Oceana 2 years ago & Aurora this year. Found that the clientele on Oceana were slighltly younger i.e. mainly 30's - 60's whereas on Auora it was definately more 50's to 80's. As I am in my 30's I definately enjoyed the Oceana cruise more. Also found it very annoying that children were allowed in the nightclub on Aurora, whereas on Oceana children were not allowed in. Love children as I do it is nice to have a kid free zone sometimes ! I also found Oceana easier to find my way round. Obviously age ranges vary depending on the type of cruise & the time of year anyway, but personally I preferred Oceana.