First let me say that we have always cruised RCCL and have always been happy no matter what size ship we were on. That said I list some Pros and Cons which are not deal breakers but are small annoyances or kudos. We work in Management so we are keen on observations big and small.
Pros
Rccl always top notch with service. From Radiance class to Oasis class we have found cleanliness and service top notch.
We always get a balcony. Cabins on all ships are small unless you get a suite. Bathrooms are so small especially showers that if I was overweight I would not fit in shower