Hope you don't mind me chimning in here,I've also sailed on Oceania....16 days Miami to LA. I lenjoyed it and at the time rated the food as the best I had eaten at sea(over Crystal and RSSC).I sailed with a friend and the beds were in "twin mode"...made for tight quarters....but doable.
At that time I said to Norma that I didn't think Ray could sail on this ship(meaning Renaissance stle), due to the rolling motion. We had NO problems with it.
I personally loved it,very friendly passangers,best Trivia at sea(ahem,we won!)
They did tend to nickle and dime you re water,etc.
Then in March this year Ray and I sailed on a 12 day Carribean trip on the Azamara Journey...another Renaissance ship...twin of Oceania.....and yup, two days out of Miami we started to roll, and Ray ,for the first time in almost 20 years of cruising was violently ill for over 12 hours.
I guess what I'm trying to say is...if you tend toward any motion sickness you may prefer a larger ship. The Oceania and Azamara were 30,000 tonnage.
One other thing, Azamara was also C.C.C. also

the food was superb,wines were reasonably priced and they made a mean Manhatten.
For a shocker check out the price difference for the two cruise lines....BIG difference.
Sorry,didn't mean to hi-jack your thread but Use either line and you will have a great cruise.